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Video tags
Subtitles
Russian
00:00:02
took a course in layout and inside triggers00:00:05
they get here to bypass the academy and00:00:07
inside the course we have layout00:00:09
dating java script so called00:00:11
basic again all materials and steel00:00:13
courses that were in the workbook they00:00:16
actually included here is that they are00:00:18
there will be here but we will stop at them00:00:19
I won't be here for long, I'll run through00:00:22
if anyone still has these materials00:00:24
some questions and misunderstandings you just00:00:26
whistle until stop stop, can I ask here?00:00:29
and then I once again do something usually00:00:31
basically I guess we just00:00:33
let's go for a run and let's go further I will00:00:35
tell only the tour what they studied00:00:39
Well, I told you that on this course we00:00:41
don't assume that we are on computers00:00:43
we are doing something yes you are doing it at home on00:00:46
layout course I can accurately enough00:00:48
predict how long it will take you00:00:50
performing some task here is00:00:52
literally someone does something unpredictable00:00:54
in 10 minutes someone does the whole week yes00:00:57
that is, we cannot sit and wait until00:00:59
someone will do it, so we endure it all00:01:01
for homework at the end00:01:04
course we will have an empty project here00:01:08
could listed requirements you now00:01:09
you probably still can’t understand00:01:11
but I have to them that is you will do00:01:13
web applications in which you show everything00:01:16
what to teach all kinds of multimedia00:01:18
touchscreen and all sorts of animations and so on00:01:21
everything we have learned00:01:23
So00:01:24
here is a link to the criteria00:01:27
the graduate will pass the assessments, that is, when I00:01:30
I will evaluate the final project I will00:01:33
look at the deck yourself when you go00:01:34
how much you this criterion each00:01:36
steam that is, as you showed00:01:38
interactive features like you00:01:39
show how you showed your skill00:01:40
communicate on00:01:42
version of the mountains in this case the verse for example00:01:45
or anything else like you did00:01:46
navigation in this single doctor children tires and00:01:49
so on now this is most likely for you and00:01:51
doesn't say anything so don't bother00:01:53
pay attention to this when we are in some kind of00:01:55
moment we're going through some topic I'll be there00:01:57
come back here and talk now you00:01:59
Do you understand how this criterion can be00:02:01
just do it for now if necessary00:02:03
look at me it doesn't look like you00:02:06
be interesting, well, everyone has a graduation project00:02:09
we're better off there at the very last00:02:10
protect you will be here for sure and and00:02:15
I probably don’t advise you in advance at all00:02:20
worry about a narrow project I have00:02:22
moment at 2 marked in my mine00:02:25
cheat sheets at what point to tell you00:02:27
guys it's time and I'm at this moment and there for you00:02:30
see where for the rocket theme you can like00:02:33
it’s like children’s where you can emphasize00:02:34
status and then at least you will00:02:36
ready to start making mine00:02:38
project now better focus on00:02:41
the material itself00:02:42
do your homework about the project00:02:44
better not to think at all00:02:46
Well, actually, that’s probably all there is to it00:02:49
this introductory part00:02:52
let's now move on to the material00:02:58
you look what I'm doing, I'm opening the most00:03:01
first topic here and so in working00:03:04
notebook is what is on the slides in different00:03:06
tabs and00:03:10
we start these little by little and so about00:03:13
variables what is a jim variable00:03:16
hide yes I assume everyone knows yes00:03:18
that's what they are called as usual00:03:23
they call it case sense yes all this00:03:26
know that every word is capitalized00:03:28
with a capital letter to us is somehow called00:03:30
who remembers00:03:32
channel created well done below what to know00:03:35
and in our00:03:38
in all modern browsers already00:03:40
modern new version supported00:03:42
java script which is called00:03:44
ecmascript 6 7 8 from whom how let's00:03:47
a little dulled because this one00:03:49
there was no sun in the basic java script00:03:51
java script was developed very very00:03:53
for a long time there were some shaggy ones and so did I00:03:55
I remember this 2 days after my wedding00:03:57
on it on December 400:04:00
but for many years he did not00:04:03
developed because he actually does not00:04:07
there is no point in developing why java script00:04:08
change if the browser is supported00:04:11
out a browser was a complete shaggy century00:04:15
new browsers were released every day00:04:17
everyone fought each other00:04:19
tried to be incompatible each other00:04:20
other, that is, the marketing kula on00:04:22
literally you know all the browsers00:04:24
internet explorer yes ok about children's who00:04:27
haven't heard00:04:29
we are a little older people there is dirt more often00:04:31
more likely he heard00:04:34
so on the Internet I won this layer00:04:35
That’s why there’s no way to straighten out the war00:04:38
you don’t know anything, but once there were two00:04:40
netscape browser on i would say there00:04:42
it's probably better like this00:04:45
it turned out that microsoft beat him00:04:47
and then others appeared00:04:49
advanced about the lake let's say more00:04:51
reliably now you are an internet explorer00:04:53
I live like this, you all think about him00:04:55
I'm afraid you don't want to use it, but00:04:57
one way or another when did these appear00:04:59
the newest browsers are already up to date00:05:02
they have a policy, something they call it00:05:05
personally strong and that is, they automatically00:05:07
are updated you know that chrome when00:05:09
any reboot of firefox is not automatic00:05:12
come forward and you always have one way or another00:05:14
latest version of the browser and therefore if00:05:17
suddenly chrome introduced some kind of support00:05:19
something she very soon ends up with00:05:22
Firefox does the same for everyone and that's why00:05:26
it turned out that it already makes sense to develop00:05:28
version of the language, that is, new ones are coming out00:05:30
language standards after some time in00:05:32
browsers are starting to support these00:05:34
opportunities after a while this00:05:37
support is already showing carcasses around00:05:39
layers of the population and then already00:05:41
developers can write a program with00:05:43
using these new opportunities00:05:45
that is, this was this breakthrough00:05:46
literally a few there five years ago00:05:49
maybe that's when it appeared00:05:52
this one like this with a mask 600:05:54
which is like it's something else00:05:56
name of the person ecmascript 6 either00:05:58
ecmascript 2015 is the same version00:06:01
language after that it is even further00:06:03
developed now there 8 maybe 900:06:05
it's convenient to say it's not that important00:06:08
but the main thing is that along with this there is racing00:06:10
Moscow 6 many new interesting things arrived00:06:12
capabilities that were not previously available in the language00:06:15
enough one of them is variables00:06:17
which are announced not through cooking through00:06:19
years so who knows about the project years00:06:22
few yes, so you have to manage and00:06:25
so when we would and you announce00:06:26
variable via war remember it00:06:29
inside the function and when the function00:06:31
ended variable stops00:06:33
act trace the same but you yo00:06:36
you can declare inside for example a loop00:06:38
they will be years old when the cycle ends00:06:41
No I see, yes, or for example, inside IFA you00:06:45
announced and inside the curly columns00:06:47
were variable through the years when them00:06:49
this variable is over00:06:51
she has time to live nothing area00:06:53
apparently this idea is not clear to me00:06:58
can be very important, we will also have00:07:00
Of course I'll tell you a lot of examples00:07:02
I’ll show you on this topic and you can eat00:07:05
declare variables or already accelerations00:07:07
variables and constants in the word konce tv00:07:09
but this is the same variable as00:07:11
years, but you can’t change its value00:07:14
is possible to declare immediately assign it to it00:07:16
the value can then be changed00:07:18
it is forbidden00:07:19
so they are called differently, mind you00:07:23
with capital letters and underlining00:07:24
between words, does anyone know how00:07:27
called00:07:28
sleep or snake case00:07:31
saw a snake00:07:34
that's why it's good here and I also have to00:07:38
say tell about strict regime00:07:40
has not yet been mentioned here00:07:42
us in00:07:45
let's say the standard old crypt00:07:47
there is actually one big problem00:07:49
there are many so-called generic00:07:51
injuries and because it was invented00:07:52
very quickly in just a few days00:07:54
the language standard was compiled simply from00:07:56
different ideas from other languages00:07:58
no one expected that such a thing would be needed00:08:01
the great popularity of this language00:08:03
will be used on there billions00:08:04
devices and therefore do not particularly work on it00:08:06
I think there are significant to the network one of00:08:09
the biggest language you probably know that00:08:12
if any00:08:15
you write like this and is equal to 5 without00:08:19
words what is happening who knows the world she00:08:23
global, that is, in this way00:08:26
global variable00:08:27
you know, yes, it’s an ambush, although that is, it’s like00:08:30
would be a function inside but on us but in reality00:08:32
global because of this there can be a lot00:08:34
shoals will not grow and will not grow00:08:37
grow up that's why because it's00:08:40
weird behavior they did this00:08:42
opportunity at the beginning of the program we can00:08:45
write this phrase in the dots yes00:08:47
strict that is, use strict00:08:49
this is the regime from now on00:08:51
the behavior simply causes an error i.e.00:08:54
the truth will simply refuse to do this00:08:56
the function will have an error in the console and that's it00:08:58
yes, we defended ourselves this way, but00:09:00
this is why this is not correct and not00:09:01
good behavior fingers still prohibits00:09:04
a couple of other unpleasant scenarios and00:09:06
this is the most important of them00:09:09
why do you think it's in quotes00:09:13
why couldn’t it be simple and strict00:09:20
no start what an interesting thing00:09:22
java script should be anyway00:09:24
combined somehow with the old ones00:09:26
browsers, imagine for example that00:09:30
imagine doing this00:09:33
language extension what you can write here00:09:36
just write the program like this at the beginning00:09:38
plus 3 all new browsers understand this00:09:41
let's say chrome firefox and so on00:09:44
it will be in the old browser, just in case00:09:46
someone will discover in the old konig that00:09:48
will happen in00:09:51
browser that I don’t know what it is00:09:53
chandelier00:09:54
mistake and we live here mistake correctly00:09:57
the entire script will break and will not work00:09:59
what will happen and what will happen if we decide00:10:03
what is she in quotes to write down what with00:10:05
from the point of view of the old browser this means00:10:06
state00:10:09
yeah, well, that is, let me explain a little00:10:11
now if we write like this wore a equals 200:10:15
plus 5 what does he do, caresses00:10:17
adds 2 plus 5 remember counts00:10:20
expression and assigns the value to that00:10:23
variable expressions from correct00:10:25
right now what if you just00:10:27
let's write plus 5 so you can write00:10:31
Is it possible to do a java script?00:10:34
will calculate the value of the expression that00:10:37
it will work out just because of this00:10:40
I thought I was strong and you didn't move on00:10:42
They said that nothing should be done with these 700:10:45
will make it clear but respected and00:10:47
it will get lost, what if you just write 500:10:51
.00:10:52
What00:10:54
he will calculate the value of this00:10:56
expressions it is equal to letters not just00:10:58
I’ll move on, it’s clear and accordingly00:11:01
what does he do in this case00:11:03
he considers the meaning of this expression00:11:06
this line doesn't do anything at all00:11:09
what next? that is, just the old browse00:11:11
ignore this line it will count00:11:13
I'm not afraid of her00:11:15
I have you go further than the head browser00:11:17
knows that this is a switch, abstract00:11:20
that is, the idea is clear they are this way00:11:23
made the violin compatible from the old ones00:11:25
with new pro services they are always like this00:11:28
trying to do nothing to spoil how00:11:31
I didn’t tell you about the hawk, I advise you00:11:33
all your program now start sims00:11:36
3 to always write we start north like this00:11:40
and proved cost I already told you00:11:46
now about simple data types00:11:51
what the hell if a tank00:11:56
means number string logical value00:11:58
true true Poland everyone knows that, that is00:12:02
well, but in reality it’s like that and then you know00:12:04
this is not a separate type there is00:12:06
the concept of an object is just empty00:12:08
object is a value of the type rest itself00:12:11
in fact there are hands for example anda will understand everything00:12:13
they know about breathing, it’s always separate00:12:16
there is a symbol, we won’t pass it00:12:19
if you want to delay part I am the highest00:12:21
moment the link is just in00:12:23
modern browsers supported00:12:24
something there might be very useful00:12:26
there is more I won’t go into the main thing00:12:28
we'll take these off for us anyway00:12:31
most of all we will work on how00:12:34
numeric strings are written00:12:36
everyone knows the constants, this is it00:12:38
about these surveillances00:12:42
yes everyone knows how it works well00:12:47
what else are the lines templates here?00:12:51
this is something that was not there during the basic course00:12:55
Joe Moscow00:12:56
or on standard ones on creaking 6 brought to us00:13:00
very important feature of the line which00:13:03
backquotes are used, notice the slash00:13:06
slash o quote back stroke00:13:09
this is their so-called template string00:13:11
there are several features 1 you are00:13:14
you can break the line into several00:13:15
lines of source code because I'm here00:13:17
wrote to that is, I could press enter and00:13:20
everything turns out that in reality this is00:13:23
this place00:13:25
in the line itself, line feed is everything00:13:29
the same as I would write line 1 slash and00:13:32
space space line 2 that is, this is it00:13:35
line feed and in before two spaces00:13:36
they are all inside the page this way00:13:39
it's much easier to write string things00:13:41
especially if someone has already tried00:13:43
for example, work with all sorts of Jason them00:13:45
xml amide in java script then you understand00:13:47
that often we have multiline00:13:49
template to fill out icon00:13:51
just like this and very easy00:13:53
take you take a ready-made template for00:13:55
backticks all the right places00:13:57
put00:13:59
extremely useful thing00:14:01
so in these lines of templates you can00:14:04
use a so-called placeholder00:14:07
that is, we bet dollar and curly00:14:10
parentheses in curly braces can be00:14:12
write down any expression she won't00:14:14
here it is simply inserted inside the line then00:14:17
there is a matrix I was a row oao was00:14:19
the value 5 is what I put in the variable c00:14:22
I put a pattern line in which00:14:26
first comes the words text here she is and then00:14:29
the value of the variable t is substituted here00:14:32
she will then pour out all the words and then00:14:36
the value of the expression plus 1 that is00:14:38
six saw how everything was laid out then00:14:41
there is if he would give me a few things00:14:42
I would have to close the quotes all the time00:14:45
plus then open the quotes again00:14:47
this is all very pleasantly mastered00:14:50
then again this one is very very00:14:52
a handy thing, actually a lot00:14:56
it is the template strings that have others00:14:58
I won’t go into depth about the new chips00:15:00
because they are rarely used00:15:02
you can be powerful if you want separately00:15:04
read00:15:05
I would probably be here00:15:07
this phrase remains from some old00:15:10
times I suppose that to start some00:15:12
version should already work by the way00:15:14
let's check where we check00:15:18
on tits on food00:15:21
the most correct condition and let's00:15:24
let's try to guess how they are how they are00:15:26
they work as they are called00:15:40
surprise of love and I don’t know how they are00:15:44
in English it is called instead of therefore as00:15:45
find it but I'll check support if00:15:48
what needs to be fixed here00:15:53
because you know that now it's already00:15:55
internet explorer he is quietly00:15:57
reborn into00:15:59
perhaps this phrase is really for00:16:01
all versions of internet explorer and00:16:03
correct data I want to forward it00:16:05
him because he could have made a mistake here and there00:16:08
one subtlety about how the lines00:16:10
presented inside the park00:16:12
yes they will00:16:14
exactly00:16:25
just about template liters00:16:28
followed by string literals this is what it was00:16:30
and before, let it be in quotes there and so00:16:32
Further00:16:35
Well, yes00:16:40
even at 500:16:42
with questions even those support00:16:43
unknown, that is probably this phrase00:16:47
let's leave it as is00:16:49
so I wanted to say now about00:16:52
internal string representations you00:16:54
You've probably heard the concept of encoding00:16:56
remember the character encoding who is which00:17:00
you know the encodings00:17:01
yes, besides utf-8, someone knows something00:17:07
yes and00:17:09
8r maybe someone heard but here00:17:12
tax encodings on the course in layout in00:17:14
including us, this is us, but this is a little bit00:17:15
talked about00:17:19
what what is important here when you work00:17:22
in other languages someone was messing around00:17:23
for example there and so on concept00:17:25
encodings for you basically represents00:17:27
yourself and have some meaning to you00:17:30
sometimes you have to tinker with data00:17:31
which came in some kind of encoding before00:17:34
you need to recode this into something00:17:36
always a whole java script problem to do00:17:38
this is completely isolated and because00:17:40
java script is always under the hood00:17:43
processes data in the format00:17:45
utf-16 16 that is all lines00:17:50
each character is represented00:17:51
with two fingers it allows you to work00:17:53
according to almost any symbols00:17:56
which exists in the world at the same time00:17:58
fast enough utf-8 is just bad00:18:01
to work inside the language00:18:02
programming because it is unknown00:18:04
how many bytes does each character take?00:18:07
you probably know what f8 is00:18:08
an English letter takes up one byte00:18:10
Russian two bytes hieroglyph four00:18:13
finger and so on, that is, for example if00:18:15
you said I want from some line 10000:18:18
characters and where is it there 100 it will have to00:18:21
count one each time00:18:23
analyzing Russian summer English years and00:18:25
how much tobacco to pass until we get there00:18:27
up to 100 force if you know for sure that in00:18:30
Each character contains exactly two bytes, then 10000:18:32
characters in the 200th byte is correct00:18:35
is it allows you to work something is00:18:37
java script decided that00:18:39
internal encoding is utf-8 so any00:18:43
almost a symbol can be represented by a string00:18:44
work quickly and any data that00:18:47
one way or another the outside come anyway00:18:49
otherwise when is encoded and represented in00:18:51
this is the top 16, that is, you are from00:18:53
Encoding problems are completely isolated00:18:55
this is a great blessing but the thing is that00:18:58
this f-16 is not really any symbol00:19:00
one can imagine00:19:01
there are characters that we don’t fit in00:19:04
into this encoding and accordingly they are on00:19:06
java script level at a little bit of Tomsk00:19:09
I love Sika for example they really are00:19:11
were occupied by two characters of some kind00:19:14
in a sense, no, well, in short00:19:16
something strange is starting to happen every time00:19:18
very rare somehow00:19:20
mental and rubles or something but just00:19:23
know that braids can be00:19:26
that's good let's move on now00:19:30
simple topic, all sorts of arithmetic00:19:33
addition and subtraction operations00:19:35
departments modulo unary binary00:19:38
everyone knows this00:19:41
ok don't forget if you can00:19:43
ask how the slings are glued together too00:19:46
everyone knows a plus sign00:19:47
good about the fact that you can use parentheses00:19:50
use00:19:52
to manage priority there00:19:55
everyone knew the addition of their operations too00:19:59
so small now00:20:02
accuracy warning00:20:09
that is, for example, we can write you00:20:12
you know what if there is something to write down00:20:14
expression it is immediately calculated yes00:20:17
Well, you see what an interesting miracle 0 2 + 000:20:20
and 1 why that one in blue 03 and a little00:20:23
other meaning is similar see 0 200:20:26
minus sailors will not respect and but 0 300:20:29
minus 0 1 already00:20:32
that is, the value is inaccurate, it is not00:20:36
some kind of java script jamb it will be like this in00:20:38
any programming language java script00:20:40
he can't count fractions himself00:20:42
this is all literally done on00:20:45
processor level, that is, for all languages00:20:48
there will only be a recipe for puff pastry, such a joint00:20:50
unless they have some kind of their own00:20:52
support for floating point operations00:20:55
for example, some scientific programs and00:20:57
so on they can have their own00:20:59
implementation more accurate from 8 to 1600:21:02
there are not enough decimal places00:21:03
calculate much more and according to others00:21:05
algorithm is more accurate, that is, it does not00:21:07
speed is important, accuracy is important00:21:10
new any normal languages and00:21:11
you get this jamb and usually again00:21:14
this jamb doesn’t bother you because00:21:16
this meaning is used and not00:21:18
show you for example why 1 300:21:21
optimal rating because you00:21:23
there were 03 rubles and you took 0 1 from it00:21:25
ruble, that is, the result will also be 0 200:21:27
ruble and the benefits you show00:21:29
user you will round to two00:21:32
decimal places00:21:34
well, even if you need two signs again00:21:37
decimal places when you buy here00:21:39
this value is up to 5 digits after you00:21:41
get 0200000:21:44
you understand that there is a jamb only in00:21:46
sixteenth decimal places00:21:48
considering what you always show00:21:51
data rounded by not sixteen00:21:53
signs and less you usually have this00:21:56
the problem does not concern but in principle too00:21:58
remember that the calculations are not exact and00:22:01
in some cases this is small00:22:02
error 16 signs it starts00:22:04
accumulate for example if you have a cycle00:22:06
or is the construction still something and here it is00:22:09
this is a mistake, it's jumping closer and closer00:22:11
and sooner or later maybe a whole part00:22:13
launch the featherbeds00:22:17
you can't count any language absolutely00:22:19
exactly the same now about the string expression00:22:22
I already asked you so you know what00:22:25
the lines stick together and so and now I want00:22:28
ask00:22:29
we can remember about those operations00:22:32
apply some operations simultaneously00:22:34
for example, to the line a number, that is, put00:22:36
some kind of operation sign between the line00:22:38
number to remember this jamb for example that I00:22:42
I can write 2 minus 1 and it turns out00:22:47
number 1 because how does it turn out who00:22:51
can explain00:22:54
to an integer in a numeric but why exactly00:22:58
numeric kill already has a string and a number00:23:01
because only numbers have a minus00:23:04
there are operations minus there are only between00:23:06
numbers so it’s clear what exactly is needed00:23:09
2 strictly 2 bring to garlic 2 before and00:23:12
after that you read the same thing00:23:15
for example, with multiplication it’s all fine00:23:16
will work but it won't work00:23:19
addition00:23:20
because there is a plus for both numbers and00:23:24
strictly so for some reason they decided what it means00:23:27
plus will result in the line me00:23:30
it seems like it's just for the sake of it00:23:31
it's easy to write down all sorts of things like there's no00:23:34
I know there's allure there's a sum00:23:39
no one knows if they were like this00:23:42
if you in case added plus led00:23:45
there is no number and there is no number00:23:48
write00:23:49
very convenient for convenient input/output00:23:53
smaller that will still be a plus00:23:55
list the names on the line, although it’s quite00:23:58
it’s better to use it for any operation00:24:01
gluing and then stuffing it to know for example00:24:03
in other languages there is for example . . This00:24:06
merging strings and plus is always addition00:24:09
It would be better if they came up with another sign, but they00:24:11
decided to take a plus from it from me to him00:24:15
such an unpleasant joke about which00:24:17
you need to remember but other operations that is00:24:21
results in a string of both operands only00:24:23
plus other operations results in a number00:24:26
even if they are valid for string number00:24:28
so that is, for example, where it is possible00:24:31
see00:24:33
look if I compare for example00:24:36
20 is less than 5 why it turns out to be a friend00:24:47
these are strings and do not compare as strings00:24:49
the first character is inserted by you five more00:24:52
everything is clear, but it doesn’t come to zero00:24:56
but that's not the case anymore00:24:59
that is, since the operation is smaller it00:25:02
valid for strings and numbers here00:25:05
jalas someone needs to choose him what we00:25:07
we will convert the string to00:25:08
number or number to line number to line00:25:11
only for plus and for all others00:25:13
cases the lines number on so it is 2000:25:17
convert to quality and compare with 500:25:19
it turns out it’s not at all clear how in this00:25:23
moment some steel you're leaving00:25:25
you're still holding on should start at00:25:28
There is such a picture on the Internet00:25:29
will fit the passage to the girl g800:25:32
you can find these00:25:35
she tried something like this00:25:37
study changed my mind study compassionate so00:25:41
and another one with these same things00:25:44
subtlety see ours including00:25:48
operation is also the same thing to do00:25:50
look at our 5 equals 3000:25:54
here because the number 5 3 barroso line00:25:57
5 is converted into the number 5 and then they00:26:00
look at this now00:26:02
something interesting should be done like this00:26:04
write yes, that is, an empty line00:26:07
remember it is converted according to the algorithm00:26:09
number if anyone has studied qs basic00:26:11
discounts paid attention when garlic00:26:14
are converted to a number automatically00:26:16
I'm glad there are several options for parks00:26:18
in the force here is one of them set then00:26:20
there is how it works exactly on amperes from00:26:23
walt strings empty string converts00:26:25
forged but not only empty noticed that00:26:28
the space is also quite the result and00:26:30
for example slash slash in any of these00:26:34
whitespace characters so-called00:26:35
remember this term is that is only00:26:38
line feed carriage return00:26:39
vertical adjustment tab00:26:42
horizontal is all the so-called00:26:44
penetrating force even if the line00:26:46
completely that this is stable today00:26:47
it is not empty at all, as you can see a long time ago00:26:50
something is, but in fact all the symbols00:26:52
there are spaces in it, there is such a term00:26:55
accordingly, ropes are formed00:26:56
Kamenyuku and accordingly it turns out that00:26:59
equality is true do hold on for now00:27:02
boring grief00:27:04
since comparison operations work with us00:27:08
you now have a little bit of just that00:27:09
touched less more it's all of you00:27:11
look at how strings are compared and with what00:27:15
the difference between triple and double is equal00:27:18
they know00:27:19
there is a quadruple00:27:22
May be00:27:24
ok, nothing to hide, it’s still developing00:27:28
so good now about the transformation00:27:31
data types this topic is on passenger those00:27:33
we have but I'm here a little let's go00:27:37
na developed yes but well here she is a little00:27:41
in more detail then let's at least00:27:42
Let's repeat briefly and so on in this topic we00:27:46
We will now study how data in general00:27:49
different types are converted to data from others00:27:51
what kind, how and by what algorithm00:27:54
this is happening now we are talking about exactly00:27:56
explore how strings are converted00:27:58
is converted into the number of what there are at all00:28:00
option that is, let's say if we have00:28:02
a string and we want to get a number from it00:28:04
which is not written down what options are there00:28:07
obvious to everyone probably known by00:28:09
remember the difference between passwords00:28:13
marshall allows fractional numbers i.e.00:28:16
the string entry may contain decimal00:28:19
point minus 38 gives the number -3, that's dangerous00:28:23
from -38 only -3 will be enough because .00:28:26
this no longer allowed everything to be read on00:28:29
skip if you give parsing either00:28:31
password any is unacceptable and significance00:28:34
already the very first character is not there is not a number00:28:37
then the answer will be to us what is everything to us00:28:40
to whom00:28:41
good and there is a separate option number00:28:45
that is, you can write to us and00:28:47
pass him some string and she too00:28:49
converted to a number but a little bit00:28:51
to another, that is, from minus 38 this is the number00:28:54
minus 38 but from 22 g we immediately get it because00:28:58
what is unacceptable here for the number 700:29:02
that is, they can parse farkhod with them00:29:05
work here's how parsing works00:29:08
he took a deuce and then [ __ ] him with ours00:29:11
no longer an acceptable number, it all means he's on00:29:14
two and stopped the answer will be two then00:29:16
there it converts the string to a number up to 100:29:19
invalid character as soon as00:29:21
met unacceptably strong everything00:29:23
transformation completed she amber if00:29:25
encounters at least one invalid character00:29:27
all at once in response00:29:29
so he makes 0 from an empty line like me00:29:33
already today he speaks and mind you even in his sleep00:29:35
mine does the same00:29:38
if you suddenly tell him what’s here00:29:40
that's all clear, okay now00:29:43
let's be a little more cunning like we already are00:29:47
today in fact look looked at00:29:50
option you can try to apply to00:29:52
string string variable any00:29:55
an operation that is only allowed for00:29:57
numbers for an example of multiplication, see00:29:59
there were twenty-five me and three me in the line00:30:01
Elena multiplied 1 since multiplication00:30:05
only work for numbers java script00:30:07
forced to translate this into a number and00:30:09
multiply by 1 and get the number 25 to00:30:14
This is a slightly more compact way than00:30:17
write number but this is so hacker00:30:19
both said and when you write a program00:30:23
in general what should you optimize for?00:30:27
what should we strive for?00:30:29
the main thing is your rights00:30:31
readability excellent summit same answer00:30:34
what is less less code water old year00:30:38
no, I want you to unlearn00:30:39
forget Nika doesn't care how much00:30:42
the code you dream about may be written00:30:44
stock code has a mind if a person00:30:45
I looked and understood everything, so that’s it00:30:48
cool cool photo so clear year00:30:51
and it’s hardest to write clearly about this00:30:55
strive exactly vodka try this00:30:56
yourself tabs visa while you and what00:31:00
developing growing students00:31:02
programmers, you will be tempted to write00:31:05
as difficult as possible once you've learned00:31:07
some trick some opportunity you00:31:09
right now you want to write exactly like that because00:31:11
that this is very unclear no one00:31:13
understand and you already understand but this00:31:15
should growth problem keep track of this in00:31:18
yourself and try as soon as possible00:31:19
translate try to write simply00:31:22
it’s not clear to write something like this00:31:24
although it is short and works just as quickly00:31:27
as it should, but why should I?00:31:30
I don't like it, whatever you want00:31:33
divide by 1 you can subtract 000:31:36
This is the result of seed one, also 25 a00:31:39
you can use the unary operation00:31:43
unary what is unary minus everything with00:31:46
us us variable was the 5th and taste and00:31:49
deduced minus this variable turned out00:31:51
minus 5a is in total if unary00:31:54
minus changes the sign of the operand then unary00:31:57
plus what does00:32:00
unary plus does not change the sign of the operator00:32:03
Why is it needed at all? It’s not clear, but00:32:05
he just does nothing but because he00:32:07
only works for numbers00:32:10
very interesting way00:32:11
converting a string to a number yes here it is00:32:15
to be honest I like it because he00:32:17
extremely compact and there you go00:32:21
some speaker more or less communication00:32:23
that is, this is often done by people who00:32:25
they want to write faster, they often do it like this00:32:28
once and for all notice that if if with this00:32:32
the number swear will do nothing if the weight00:32:35
this line you will get a number, well, sort of00:32:38
ok interesting technique00:32:41
but if I for example try to add with00:32:44
zero then you see the transformation is not00:32:45
it turns out I get the result00:32:47
because it's a plus for the slings00:32:50
between what number of guests00:32:53
Well, these methods are clear, but nothing00:32:58
there is probably nothing particularly new for you00:33:00
was now how can we check00:33:01
conversion result00:33:03
note that in some cases after00:33:05
converting string to number we00:33:07
we get and we need to check a and00:33:09
did we succeed, that is, if we succeeded00:33:11
will appoint, for example, a person to drive00:33:13
age, this is the right figure00:33:16
so you need to try to check them00:33:18
long archive here's how it's correct00:33:21
do something that just compares with on00:33:23
we won't get a protective result00:33:25
now I will show you that I was 55 weight and00:33:28
I transformed him through the fleet into00:33:34
number that is, sleeps like you number00:33:36
the value in it is 55th using the function and00:33:40
I knew they were checking and we weren’t sleeping in this one or00:33:44
no she's in front of no then I need normal00:33:47
the number there is 55 to a00:33:50
now look I take psst from and00:33:53
I transform society and it turns out00:33:56
pregnant woman sleeps I understand everything00:33:59
why before00:34:01
[music]00:34:07
this one is nothing at all00:34:11
like this now look why not00:34:14
get equality don't look I00:34:15
I'm trying to check for equality sleeping and00:34:19
we don't and00:34:21
triple equals also no, that is00:34:24
the speed variable exactly lies on but00:34:27
comparison operations won't work for us00:34:31
special meaning00:34:32
special numeric value she00:34:34
so special that she even00:34:36
not equal to oneself00:34:38
it’s clear that this is usually the case at this moment00:34:41
sides00:34:44
you see, I tried to call it but00:34:48
still not exactly to here but from00:34:51
using the function and knew I could check00:34:53
you see it turns out to be hard work I heard00:34:55
says yes indeed in the variable00:34:56
sleeping lying on well, that is, this00:34:58
a reliable way to check and lies them00:35:01
variable sleeps in such a clear language00:35:03
like this, check a and accordingly00:35:07
this is the variable and she knew00:35:09
expects what type of argument00:35:15
note the number00:35:17
because in this case we are a variable00:35:20
functions and knew passed the number to00:35:22
variable sleeps lies the number to us it00:35:26
numeric constant, that is, numeric00:35:29
the variable can contain the numbers 5700:35:32
and may contain special numeric numbers00:35:34
constants00:35:35
plus infinity minus infinity00:35:37
plus 0 minus you are all numbers00:35:40
constants00:35:41
special numbers special feelings and java00:35:43
script can work with them, it can00:35:46
for example add infinities00:35:47
infinity what happens if you add it to00:35:49
infinity infinity00:35:51
correct, what if infinity is divided00:35:53
on indefinitely so there won't be00:35:56
uncertainty has such meaning too00:35:58
I think it just works out for us00:36:00
simply che but one way or another there is00:36:02
rules for working with infinity not with00:36:04
these are a plus but you also need to cook so on00:36:06
from us they are all sewn up in this00:36:09
processor in its processing of any00:36:11
numerical operations00:36:15
that is, he knew exactly the number was expected if00:36:20
we give y the number he says is00:36:23
whether this number is a constant for us or not00:36:25
is but if we give the line inside out00:36:29
it first converts it to number a00:36:32
then he says whether we succeeded or not00:36:35
that is, 55 is easy to convert to a number00:36:38
the correct number was 55 so00:36:40
answer minced meat and 55 m when converted to00:36:44
number of bits for us00:36:45
so the answer here is clear how it worked00:36:50
Now I didn’t know this function but we00:36:54
has been working for centuries but already enough00:36:57
For a long time there has been such a thing in the mountains. Not00:36:59
I knew it worked a little reliable00:37:02
understand a little she always expects that00:37:05
this argument is exactly the number if you00:37:08
pass strictly as an argument00:37:10
she won't even check00:37:12
it will work min it won't work out everything00:37:14
red numbers means the answer will be immediately00:37:16
falsehood, in many cases it is convenient00:37:19
that is, look, here I am again, the same thing00:37:21
got variables sleeping he's very on me00:37:23
asked to check this function in English00:37:26
then she says yes but when I do this00:37:29
functions are passed strictly 55 she immediately00:37:32
minced meat is burning, she doesn't try this much00:37:34
convert to number this first00:37:36
faster in the second more reliable in most00:37:38
cases we need exactly this we will win00:37:41
that's why we recommend this polarity00:37:44
use and there is another function from00:37:46
she sits and checks not on us but on00:37:49
basically checks it turned out ok00:37:50
cleaning or some special thing00:37:53
there is, for example, something that can be special00:37:55
by number it can divide infinity 500:37:58
zero will be infinity00:38:00
accordingly she says these from them00:38:02
no normal number minus00:38:05
infinity is an abnormal number, but 700:38:07
normal number00:38:08
a7 string is again converted to00:38:12
the number turns out to be 7 and she speaks00:38:14
small00:38:16
I'll get a7m, they give it to us, but it's not00:38:20
a normal feeling, that is, sometimes there is00:38:22
it makes sense to check, it happens that in00:38:24
as a result of some calculations may00:38:26
you will get such specific things00:38:27
like caldari infinity this one00:38:29
the function can be easily checked00:38:32
turned out to be a normal number or00:38:33
some kind of infinity00:38:36
and so look we transformed00:38:38
now the lines into the number and showed that00:38:41
it turned out now from the number strictly this00:38:45
it's easier here everything is easy again00:38:48
string option note that these are00:38:50
options will be everywhere the type name00:38:52
string number boolean and then in parentheses00:38:55
some meaning like that in many languages00:38:57
done when forming a data type00:39:00
gave out different types, that is, this one here00:39:02
thing it converts this number to00:39:04
line here I had a number - 38 I00:39:06
converted strictly got fear from us00:39:08
38 the easiest direct descent and then00:39:12
any data type has a special00:39:15
method is probably a word many people know00:39:17
and suga00:39:19
. string has a number, that is, a string has a number00:39:24
Many have a logical meaning. that00:39:27
string and when you describe your00:39:29
objects, garbage cars, what other things are there?00:39:31
something you can ask how it works00:39:33
this method is like your machine00:39:35
converted to a string as it looks like00:39:38
world if you output you have an object00:39:41
class machine and fish you enter into00:39:43
console what should appear from the console00:39:45
So you just defined this method and00:39:48
say my typewriter when it comes out00:39:50
the console should look like this00:39:52
for example car number and brackets00:39:54
owner we ask ourselves how she is00:39:57
looks like a string accordingly here00:39:59
my number is 38 and I said I want to00:40:02
the console of his converted strictly Ivan00:40:05
I will get the text representation strictly00:40:07
-3800:40:09
then again you can glue it with00:40:12
empty line remember how plus works00:40:14
accordingly, we have minus 3800:40:16
they glued it with an empty line00:40:18
I got line -38 this method is often00:40:22
applies again because00:40:24
compact and00:40:25
the usual one we have too00:40:29
I see more and more people doing this00:40:32
I don't know how to use the pattern string00:40:34
I like it I think it's a lot00:40:36
I have already decided to show what was written down so that00:40:38
I would also like to introduce you to these and so many00:40:40
we have studied the template accordingly00:40:42
look what I got00:40:44
the variable in it was -38 but in the console00:40:47
derived a strict template in which00:40:49
the value of the variable m is substituted00:40:51
Naturally it turns out spartan00:40:54
that's a lot00:40:56
it’s written there in a complicated way, that’s why it’s not00:40:59
I like it, everything is clear here too00:41:02
lackey and now how do we convert00:41:05
biological logical type I remind you00:41:08
we have a corpse in Poland up to 2 meanings again00:41:11
you already know option any value00:41:13
we take boolean from it, that is, and00:41:16
type name and brackets00:41:18
these are the numerical values00:41:21
that is, empty substance00:41:27
[music]00:41:33
[music]00:41:36
only this is an empty number this is empty00:41:40
line and the breath of the gift is special00:41:42
the value is again empty, well they let it in00:41:44
object and this is a special one above00:41:47
which, as it were, is not a number, these are 500:41:50
they have meanings in this way00:41:52
transform in Poland everything00:41:54
the remaining values will be given if in the line00:41:57
she deserves one space00:42:00
for example here is a boolean from 9 goals and00:42:06
hacker's way to double negative00:42:09
if we haven't stopped now00:42:11
remember we have logical00:42:13
operations logical and logical or a00:42:17
to say this is not logical00:42:20
there is a denial that is if he has00:42:22
operand corpse then deny it00:42:26
will reject and give falsehood and vice versa, that’s all00:42:30
understand accordingly if we write00:42:33
two ! it turns out that with this value00:42:35
nothing will change, it will change twice00:42:38
is denied and the result is the same as the gulag00:42:40
But ! this is the only logical00:42:44
operations sense she only has it00:42:46
for boolean values therefore having met00:42:49
! java script will be forced with00:42:52
convert boolean value here00:42:54
this way and then again00:42:59
turn it over and in the end after this00:43:00
the device brought us together00:43:03
converted to boolean00:43:04
a little hackish but compact yes00:43:07
that's why I use it often00:43:10
Well, that’s also clear, so let’s go now00:43:13
from numeric to logical00:43:16
so I wrote it wrong here00:43:19
here we are on the contrary on the environmental00:43:21
numerical00:43:24
we have a mistake00:43:31
in the workbook completed completely in00:43:33
header voltage and I in the web version I00:43:36
I'll correct myself, that is, we have a logical00:43:39
value and we need to get00:43:41
the corresponding number is when you00:43:44
apply a set to a boolean value00:43:47
you get 100:43:50
that is, the finger is up to 0 labor and st-1 actually00:43:54
actually a useful thing when you erase00:43:56
homework you're in a couple of places00:43:57
you'll come across that this is the trick00:44:00
allows for frequent recording compact grip00:44:02
and compact sometimes means clearer00:44:05
usually against compactness if it is in00:44:07
damage clarity but sometimes vice versa00:44:09
it turns out the compact year is very clear00:44:10
because it doesn't even need to be broken00:44:12
on different lines I can understand this00:44:14
this suits cover well it happens00:44:17
healthy00:44:19
so this topic is already finished00:44:24
I hope no conditions00:44:27
so here we are now, look at me00:44:30
Now let's look at an interesting topic00:44:32
we'll do it later in front of us approximately00:44:35
at 11 o'clock there will be many where 15 who00:44:39
smokes to talk00:44:41
yes that means you can be a bottleneck00:44:44
because what the hell, you won't be here00:44:46
go outside right so when00:44:48
I'll say break and immediately00:44:50
drive to as fast as possible smoke and I00:44:54
then I will forgive the attention that you00:44:55
came back or didn’t come back so it’s possible00:44:57
was to continue therefore not00:44:58
stick around so look what we have00:45:00
interesting thing is starting00:45:03
interesting things what is logical 1 and00:45:07
everyone uses it yes yes I think everyone does00:45:09
understands how it works you assume00:45:11
that you use it with logical00:45:13
meaning you already know what if it00:45:15
use with other meanings00:45:16
since this is a java logical operation00:45:18
The script converts everything to boolean this00:45:20
as if it’s already obvious I think it’s you00:45:22
all background now let's go a little further00:45:24
look what happens when we do it00:45:28
this operation is fake 3 why00:45:32
the result is false00:45:34
so the hard part is the true part00:45:38
yes, we have operations and that’s why00:45:39
the result sometimes seems to be clear00:45:41
and now look how00:45:44
this is what happened, that is, this is what happened00:45:48
like Poland, this is like labor00:45:52
for some reason it turned out to be fake and a corpse00:45:57
The question is clear, but what kind of [ __ ] is this?00:46:01
the trick is only in java script I often00:46:03
I'm trying to understand when I show up I'll show you right away00:46:05
restaurant because it is wildly healthy and00:46:07
it then grows further in react00:46:09
goes on and on and in many places00:46:13
so look at the good result00:46:16
look what to do is pitiful00:46:18
affects and he and operations he00:46:22
evaluates first operand and blind first00:46:25
Well, almost always remember the expression00:46:27
java script calculates00:46:29
what is the first operand equal to and since it00:46:31
and incense is false the second operand is possible or not00:46:34
consider it correct as if the answer already exists00:46:37
can be very useful because here00:46:39
for example, maybe there was some kind of challenge00:46:41
function it just doesn't get called00:46:43
just much faster therefore the answer00:46:46
immediately minced meat but there without working in any way00:46:49
language but in the java script the answer is00:46:52
not false, but the answer is the first one itself00:46:56
argument which in this case is so00:46:58
it happened early00:47:00
accordingly, right here now00:47:02
understand how it works compassionate sees00:47:04
logical means he understands that00:47:07
screwed up but the operation is logical he00:47:09
calculates 1 operands it turns out00:47:12
falsehood transformed ecological00:47:14
values and therefore there is no need to calculate 200:47:17
but moreover, the meaning itself is00:47:20
the first operand is not false but the result00:47:23
will be equal to the first operand00:47:26
while it’s wildly unclear why or00:47:30
someone understands00:47:31
yes just for now believe that it is very00:47:34
it's very important it's very convenient00:47:36
can't mean accordingly, well00:47:39
since the first operand is superimposed this00:47:41
it is precisely this that is the answer, not falsehood, but00:47:44
the same operand that00:47:45
transformed falsehood here orbital00:47:48
liters answer on breathing ok I saw that00:47:51
that is, for now we are simply considering00:47:53
cube yes, that is, it’s like a feature00:47:56
how she uses herself it will already be00:47:58
in this lesson now look what00:48:01
it happens to us if our hands are 1 grand00:48:04
truth or is brought to truth00:48:06
first operand is true00:48:08
look what happens in the operation00:48:10
logical and if the first operand is equal to00:48:12
true what the answer is equal to00:48:16
it doesn’t necessarily depend on 2 grands00:48:19
if 2 there will be a false answer false if00:48:22
2 corpses everyone understands the answer, that is00:48:25
the answer is the second operand00:48:28
saw yes yes just the same logic00:48:31
stuck on bending because and when there will be00:48:34
written down then the answer is00:48:37
since 7 is given by someone's answer00:48:40
is 5 because 5 reduces to00:48:44
structure the answer is 7 note and00:48:48
what you get from changing the positions of the operands00:48:51
the result depends, this is also important00:48:55
so now this operation and00:48:58
considered a similar symmetrical00:49:00
fun of working with operations and that is, weight00:49:04
our first operand is true00:49:06
operations from it the second trend can not be00:49:08
it is clear that the answer is already here00:49:11
if the first operand is cast to00:49:15
so you already know up to 2 grant is it possible00:49:18
consider the answer to change the first statement00:49:20
Now, if the first operand is 7 2, you can not00:49:23
consider the answer is Samokhin that is00:49:27
for the game and what was given, well, here it is00:49:31
similar operation not if the first00:49:34
the operand is false which means the answer depends on00:49:37
the second operand, that is, the second operand00:49:39
and the answer will appear00:49:41
00 this is false means to stand out with the answer00:49:44
Well, this is minced meat, which means it will appear00:49:47
everyone feel the logic here everywhere00:49:50
absolute symmetry of everything to the utmost00:49:52
logical, but it’s just not clear yet what for00:49:54
what the hell, I'll be a little later00:49:57
having corrected it, I need to say something00:50:00
these00:50:02
good ones, nothing interesting here00:50:04
No00:50:08
passes00:50:10
so the input/output operators are about alert00:50:14
I know the console for everything, so nothing here00:50:17
such00:50:18
nothing special00:50:21
so now what is here little one would like00:50:23
add in combat projects as a rule00:50:26
all these operators are together by gender00:50:30
display on a cat that is not a wall and00:50:32
they poke around, there’s no reason why they can’t be stylized00:50:35
strong for safety reasons00:50:37
Is there something missing from your website?00:50:38
asked and you didn’t even understand what00:50:41
in fact, they carried their password at all00:50:43
Not00:50:44
somewhere but not windows for example00:50:47
I recommend it, but in reality it’s like this00:50:49
very little protection of course yes because00:50:52
that a person can still write to you00:50:55
a page that looks whatever you want and00:50:57
I still ask you for anything00:50:58
but nevertheless for some reason it is believed that00:51:01
These windows should have been banned00:51:04
sterilize00:51:05
Accordingly, they are almost never used00:51:08
web pages usually ask some kind of00:51:10
questions or accept answer from these00:51:12
thoughts whose form is stored00:51:16
it seems like they still grow somehow and00:51:18
do not use torsion bar sandra operations00:51:23
so now switch00:51:26
so I guess I know how to do it00:51:29
works00:51:30
and switch it and stop for whatever I want00:51:32
pay attention, you know that java00:51:34
the script considers this expression and will00:51:36
compare it with this value this00:51:40
meaning00:51:41
the expression itself betis is compared00:51:43
values without when looking low, that is00:51:46
if the number here is 5 guests00:51:48
again if you're free00:51:53
suddenly00:52:02
over the poor other operations00:52:05
Vladimir00:52:08
Everyone knows about the ternary operator.00:52:10
whose three operands you understand as he00:52:13
works and00:52:14
Is anyone embarrassed about any questions?00:52:17
no question no one is embarrassed00:52:19
Raise your hands who is shy00:52:21
set00:52:26
this is a very useful thing00:52:30
used many times explained many times00:52:32
where it is explained quickly so let's00:52:34
I’ll just repeat that there are three operands00:52:36
here are the first second and third java deaths00:52:39
consider the meaning of this expression and if00:52:41
it is true then this is the meaning in00:52:43
variable and if false then this00:52:45
Everyone understands the meaning of tattoos well and00:52:49
we have just such an operation which00:52:53
called type of it allows00:52:55
check00:52:56
argument which is visible to the argument of this00:52:59
operations notice this is exactly the operation00:53:02
Usually operations are designated by different00:53:04
icons like plus multiply and so on00:53:07
but there are no kupa icons for all operations00:53:09
Enough some transactions are recorded00:53:11
in words this is one of these one of these00:53:14
examples, that is, look at me00:53:16
variable age number accordingly00:53:19
type of each task on00:53:21
and after that you can put a space00:53:24
can you use it and what works?00:53:26
the same, but I don’t dream anything again00:53:28
because this is an operation let it be00:53:30
write minus x or you can in Minsk00:53:32
in parentheses without changing anything strange00:53:34
so this is also relevant for this OS00:53:38
gasped the result is firing yes that is00:53:40
this means actually an object object and00:53:43
we'll still go through it, well, he needs it00:53:46
how there shouldn't be an object but we haven't yet00:53:48
links are simple then a link to and like this00:53:52
called and probably many people know at school00:53:54
object maybe I can't say that00:53:56
the word is again given to the State Duma to rest00:53:59
All options are listed here00:54:01
maybe this mute function is probably here00:54:04
no again symbol but in modern in00:54:07
browser must also be separately00:54:09
return character type00:54:11
and another operation which00:54:14
called instances now00:54:19
it allows you to check how it is supposed to be00:54:22
not to this object to this class00:54:25
we have not yet studied Serbian objects00:54:28
programmer is not why you will understand the meaning by00:54:30
about so simple a basket for example00:54:32
you described the class as a typewriter and00:54:35
wrote the class helicopter you created00:54:37
several variables machine to helicopter00:54:39
and you can check this variable00:54:41
she is a true force machine yes then00:54:45
is is is not the answer00:54:49
me and examples of using this operation00:54:52
they will also show it when we study00:54:54
an object-oriented program can00:54:56
so now the while do-while for loops are all00:55:00
know how break and break statements work00:55:03
continue00:55:04
everybody knows00:55:08
about the cat and about you00:55:11
so about both so I'm here right here00:55:14
on the break I have one of the examples00:55:16
one of the layers, yes, that is, look at what's on00:55:20
in this example I wanted to show00:55:22
by using00:55:25
firstly in the for statement remember there00:55:27
three components that are in vain. They00:55:31
all optional00:55:33
they can be omitted but semicolons00:55:35
necessarily, that is, in this case it is00:55:37
means the following00:55:38
bottom club is variable c with00:55:42
value 25 in each iteration of loop c00:55:45
increases by one and second00:55:47
component we write conditions00:55:49
continuation of the cycle remember the conditions for now00:55:52
it truly the cycle continues to spin00:55:53
if I didn’t write the condition in, it means it’s a cycle00:55:57
eternal, that is, the condition of continuation00:55:59
all ranges are empty, that is, this is it00:56:01
example of an eternal cycle I don’t like this one00:56:04
recording I show I believe that if00:56:07
if you can't fit your loop into00:56:10
simple circuit variable such and such from00:56:12
five to eight don't use the form00:56:14
use while between only this is it00:56:17
the recording is very hard to read and unclear00:56:19
why do you need this form?00:56:22
this variable needs to be visible from00:56:24
now until now then how beautiful the shape is so00:56:29
Let's say we want to solve a problem for us00:56:31
you need to find the first number after 2500:56:34
which is divisible by seven I will organize00:56:36
infinite loop from 25 see00:56:39
infinite and in each body of the cycle of each00:56:42
iterations of loop c increased by one00:56:45
that I am the body inside and remember this00:56:47
called the body of the loop until00:56:49
what do I do in the body of the loop I check00:56:53
is the value divided? This is clear and00:56:56
this is for her00:57:13
that is, the operation gives a percentage00:57:15
the remainder of the division of Circus Massimo00:57:17
accordingly, if the remainder upon division00:57:19
the price of 7 is 0 and therefore c is divisible by chi00:57:22
right it turns out so how00:57:25
only we will find a c that is divisible00:57:27
at seven we stop the cycle break00:57:30
means stopping the cycle completely, that is00:57:33
termination cyclone cycle ends00:57:34
immediately and we go to the operator00:57:37
which was after x00:57:39
so it’s clear how break works00:57:42
yes it turns out that when c is equal to 25 this00:57:46
the myth doesn't work then c equals 26 of them00:57:49
doesn't work c 27 their doesn't work a00:57:52
that's when 28 of them work anyway00:57:55
the break loop is triggered accordingly00:57:57
ends in the console it says why00:58:00
why one goal here it is 2000:58:03
so okay everyone remember how it works00:58:06
break00:58:07
and now about that means you asked about00:58:11
I have a container with a following example:00:58:13
I'm talking about the config, so let's00:58:15
we'll try to remind you on the board there00:58:17
This00:58:18
I will let you study what I won’t open00:58:20
now out of cycle00:58:29
writes00:58:31
You00:58:39
yes, that is, look, let’s say our task is00:58:41
display all house numbers in the console00:58:44
odd side main 13 because00:58:47
1300:58:48
unlucky 40 before that is filling us00:58:52
variable canvas loop you see goes from 100:58:54
up to 11 step 2 so that is, if only00:59:00
if it weren't there it would be in the console00:59:02
turned out to be house number 1 ton vr3 house00:59:05
number 5 so 21900:59:07
but it was for house 013 that I wrote00:59:10
containers container means what is needed00:59:13
finish00:59:14
current iteration for the year, that is, if00:59:17
break ends the entire loop to continue00:59:20
ends only the current iteration and00:59:22
remember this is called the body00:59:24
loop and this loop body is executed a lot00:59:27
once and then each execution is called00:59:31
interactions yes, that is, for example, look00:59:34
when let's say in a situation where x00:59:37
fell asleep equals 9 this one doesn't work00:59:41
the console is displayed then number nine00:59:44
then this statement is executed00:59:46
it turns out halfina 11 doesn’t work00:59:50
went next terraces heat them not00:59:52
triggered in the console the house number is shown00:59:54
11 iterations and ended with Hausu00:59:58
becomes equal to 13 next begins01:00:00
operation iv fires therefore iterations01:00:04
ends right there doesn't reach here01:00:07
let's move on to the next iteration, that is01:00:09
cold 15 iv no longer triggers01:00:12
console street house gaff 15 to clear01:00:15
the idea is everyone accepts everything accordingly01:00:17
consoles will see 1301:00:26
that's what I wanted to show me now01:00:28
in this example01:00:30
these three for loops they are all like this01:00:34
make 1 skin they look some kind of arc01:00:37
to the console five times01:00:39
watch 5 again bbc everyone knows what01:00:43
the console works like this if it's the same01:00:45
it's easy to withdraw several times01:00:47
shows how many times this is not a program01:00:49
started sleeping does this console work01:00:52
The next question is what do you think?01:00:55
better recording01:00:58
Why01:01:03
that is, there are three ways to make 1 skin like this01:01:05
but they have a Siemens wedding01:01:11
any ideas brother01:01:14
what what have you arrived01:01:16
I agree with the usual, that is, actually01:01:20
in fact, everyone always writes in the usual version01:01:22
I’d like to tell you why now, but what are you01:01:25
do you mind if you forget about01:01:27
the habit that you see others like this01:01:29
something01:01:32
yeah, look at the first ones from where 601:01:36
and here 6 we need to do something01:01:40
five times what does it have to do with us01:01:44
Then we will study this concept with you01:01:45
how to design and01:01:47
programming01:01:48
this is the anti pattern called01:01:50
magic is necessary magic constant that is01:01:53
some number where it came from not01:01:55
it's clear if suddenly you imagine that01:01:58
the program has been carried out to you five times01:02:01
the command is given, you know it’s no longer 5ok01:02:04
you open the program and want 501:02:06
change to 7 correctly there is no 5 and01:02:10
this case is of course obvious but01:02:12
make the race harder and try the teams01:02:16
it says 4 which is almost a quantity01:02:18
cardinal directions or something that is it01:02:21
need to change for 5 years and other than you01:02:24
you don’t understand that’s why the first option01:02:27
the bad thing is that there is a doctor needed01:02:30
this is basically the last option too01:02:33
not bad but purely accepted01:02:35
programming, start all cycles from01:02:38
zero and01:02:39
finish the operations less they01:02:43
less than or equal to, that is, they start from 001:02:46
before reaching 5 they reach again01:02:52
feel the difference between these and 501:02:55
loops are usually done for any01:02:58
that is, if you remember, they cannot and01:03:01
mathematics, then we write it down here01:03:04
so 05 me including01:03:07
remember, as a rule, all cycles turned out to be01:03:11
they do it this way it went apparently back in the day01:03:14
when you wrote on the server because01:03:16
there it is more convenient to start from scratch, that is, if01:03:18
the cycle starts from 0 usually and year01:03:21
in short, it works, it's fine, so be it01:03:24
as it became customary in fact01:03:28
nothing so bad about the last one01:03:30
option not yes, well, purely traditional01:03:32
the option is used01:03:34
so I recommend using it01:03:37
especially when it might be important01:03:39
when you have a job for example01:03:41
write the code the way you want, I just write everything01:03:43
it was great then that is all three of you01:03:46
programmers all the other mighty can01:03:48
write and no third option01:03:49
problems but if you are doing a test01:03:51
task for some company, each like this01:03:54
here's a [ __ ] hook, call extra there01:03:56
extra questions someone who01:03:59
your code is this review and we will go there too. This01:04:01
where you still have to retrain01:04:04
why did he write so extra01:04:06
questions with niko it's better to do something01:04:08
more secure01:04:10
it's reliable and it won't cause any unnecessary problems01:04:12
the question is why I asked him01:04:17
Well, now the topic of strength begins01:04:20
vital functions functions we actually01:04:22
In fact, we studied the java script base in course 101:04:24
but we studied them very very much01:04:27
compact to literally introduce to01:04:30
in fact functions are a huge topic and01:04:32
quite difficult, we'll try now01:04:34
go deeper and the functions actually01:04:37
java-script well, just everywhere but just in01:04:40
all functions in general in java script are01:04:43
this type of data is another one, that is, in01:04:46
the variable can be a number or it can be01:04:48
lie functions you can call01:04:50
function and argument and pass the function01:04:53
function when it returns something01:04:55
can return a function that's all01:04:57
sounds really cool01:04:59
It's weird that not many languages do this, but01:05:01
It's very flexible very side yes. Yes you01:05:04
Once you master it you will understand how it works01:05:06
it's just brutally bright and so for01:05:09
started just repeating a simple 10001:05:11
that you probably know what we have for01:05:14
In general, a function is usually needed because01:05:16
that we have some pieces of code01:05:18
repeat, that is, they need to be performed01:05:20
many times you wrote a function01:05:22
for example which is love or01:05:24
sokos then you can call them later01:05:26
got it if it later turned out that01:05:29
It's more that it's a leap year01:05:31
the legs are not so easy to determine, but01:05:33
so difficult for you, you did it in one01:05:35
where you rewrote the functions I will add01:05:37
video and it continues to work like01:05:39
abortion is very, very healthy and so are we01:05:43
Fully describe the description first01:05:45
didn't do anything. only java script01:05:48
remembers that it is there and then it01:05:50
call many times she gets01:05:53
arguments that is, we have a concept01:05:56
formal and factual arguments01:05:58
description of fruit you write formal01:06:01
benefit describe the function in glasses01:06:04
indicate formal and bright, that is, those01:06:07
some changes with which you will01:06:09
then work inside the body and when you01:06:13
call the function you already specify01:06:15
specific value that is reduced01:06:18
this is formal, well, that is, this01:06:21
these are formal and this01:06:23
actually01:06:24
just so you know the terminology like this01:06:28
sometimes they say01:06:29
each function can return01:06:31
the result and javascript of the functions are always01:06:34
returns the result if you don't enter anything01:06:37
returned she will return antifa no just01:06:39
it will happen on its own, yes, that is, no01:06:42
It’s impossible for her not to return it so easily01:06:44
It happens01:06:45
so but now the syntax is first01:06:49
we are considering the traditional option01:06:51
we now have two options01:06:53
description of standard function01:06:55
classic arrow functions about arrows01:06:57
I'll tell you more, let's first01:06:58
classic version and so the words function01:07:01
and then with them functions and in brackets01:07:03
formal then in curly braces01:07:06
function body is written01:07:09
Curly braces are required even if01:07:11
body consists of one operators all01:07:14
equals01:07:16
here inside this body you can return01:07:19
some return value and something yes01:07:22
the function stops working at this moment01:07:24
or you can just write res that01:07:27
in this case it will happen01:07:30
Andy Farid dodges this is all to01:07:33
write return on define01:07:35
because she definitely has to01:07:37
return means here I am, let's give it to you01:07:40
I'll tell you a little interesting thing01:07:43
this summer01:07:49
in fact the city is a chance collective you01:07:52
you know what at the end it’s like without a period01:07:53
are put . , everyone saw it.01:07:56
she definitely01:07:58
You don’t have to install it, everything will work01:08:02
in the same way there is a very, very plus flow01:08:05
cases when behavior depends on01:08:08
Is it worth it? he's so startled that01:08:11
you can completely ignore them01:08:13
you may never be worth it but01:08:16
traditionally we set01:08:18
you clearly tell you always remember java01:08:21
script like any programming language01:08:23
more your assembly we will apply operations01:08:26
we say which teams will start we say01:08:30
I use the create a pregnant woman function01:08:33
assigned 5 understand this is an imperative01:08:36
fall team we deliver can deal .01:08:40
6 means01:08:41
do how not to talk about different things01:08:45
do it together, watch me write the left one01:08:48
the heel also clearly needs to be returned01:08:50
feelings 501:08:53
so that if we write01:09:02
he will fall down what happens from the point01:09:04
Justin's view of who eto po will end01:09:06
here and watch the Baltics together we01:09:09
get drunk for there wore a equals 5 plus 701:09:13
same 1 elevator you know, just really strong01:09:16
sad other line what's the problem01:09:17
yes this is a continuation of the same design01:09:20
not to be mistaken, but this is where he will be mistaken01:09:23
puzzles because arrest is the only one01:09:27
operator who can after him can and01:09:29
Serbs and maybe not go01:09:32
understand the only one that's why in01:09:36
this place is a jamb you should do what01:09:38
spend something to write down exactly in that01:09:41
same page but at least start01:09:44
You can continue later, but now01:09:46
let's see let's assume that01:09:48
we need to return some beautiful carved01:09:51
for example, we want to return the design01:09:54
following01:09:56
calculate something there for 2000 plus01:09:59
calculate something there for 200101:10:02
and plus there’s something else there for 200201:10:07
if you move this first cold01:10:10
it's not just ugly here you look like01:10:13
easy to read, you can see that you need to do it three times01:10:15
cause the same thing to add it all up.01:10:20
it turns out very well and sometimes it happens that’s a plus01:10:24
the lines also turn out very beautifully01:10:27
I would like to think of one01:10:28
table but as you know Undyne will return01:10:31
Maybe01:10:35
boil down to thermal power01:10:38
that is, once you put a parenthesis01:10:41
for you this understands it all started01:10:43
expression he reads it to the end that is01:10:45
the main thing is to start your path in the line even01:10:47
if it started just how long01:10:49
which and what to remember for hockey01:10:52
come up with a simple thing effectively01:10:56
so let's look further01:10:58
here is the function called earlier and01:11:01
snorkel and tell me actually01:11:04
these are the meanings I’ll show you all right now01:11:06
examples they are presented instead01:11:08
formal arguments and when it works01:11:10
only function bodies these are the changes01:11:12
it's already 5 o'clock, that means01:11:15
so let's give a simple example, we have it01:11:19
for java courses we describe our fate01:11:21
function to get days of year quantity01:11:24
days as that is the function to get the year01:11:26
after all, functions need blocks to work01:11:28
she counted how much and how we did it01:11:32
do we check shares any 2401:11:35
if they divide we return 366 means 36501:11:38
so everyone understands what is written here before01:11:42
So this is our first time using this function01:11:45
called with the argument 2013, that is, this01:11:48
moment there was a transition here01:11:50
this code was executed and er01:11:53
it was equal to 2013, that's accordingly01:11:56
returned 365. feature in01:12:00
thirteenth year, that is, and then we still01:12:03
since the same function caused horrors among01:12:05
cops 2012, that is, five happened01:12:07
transition here and variable n formal01:12:11
arguments to actually assign01:12:13
actual value 2012 earned from01:12:16
despite the fact that bright is already equal to 201201:12:19
accordingly yf worked and returned01:12:23
366 so everyone understands how it works yes01:12:26
seems to be more or less a basic thing01:12:28
Now they are teaching subtleties that were not there01:12:31
aware of basic java-script01:12:34
look firstly we can call01:12:37
passing the function and not all the arguments01:12:40
for example, look I described the function01:12:42
which takes 3 formal arguments01:12:44
about the father and displays them in the console01:12:47
separated by flash drives but called her with01:12:50
one organ 5 respectively 5 is01:12:54
actual value01:12:55
For01:12:56
[music]01:13:11
that is, five is the actual value01:13:13
for an argument and a for a fighter and nothing01:13:17
passed it on, consider me to pass it on01:13:19
command01:13:20
that is, the breeze function poured into the console01:13:22
5 2 it’s clear how it works okay now01:13:27
how Moscow 6 brought us a new one01:13:30
possibility of argument values according to01:13:32
by default, that is, I have the hryvnia function01:13:34
said that he has three arguments and if01:13:37
suddenly you will not be on the shore then assume that01:13:40
anal 111 that's accordingly here I am01:13:43
called this function with five and01:13:45
look what happens I instead of a01:13:47
passed 5 here it appeared instead of b I01:13:51
did not transmit anything and therefore it is equal01:13:53
111 but instead of c he did not convey anything and01:13:57
there is no other meaning to keep silent either, therefore01:13:59
it rests equally01:14:01
I see, but what if I gave all three?01:14:04
accordingly, all three are derived then01:14:07
there is 111 it won't work at all01:14:10
[music]01:14:12
Well, it was clear, okay now01:14:16
look what an interesting new thing they have01:14:19
we have01:14:20
first we have an array of arguments01:14:22
secondly, half the way is not strange01:14:26
official term and that is on the way01:14:29
we are an array, I will now try to explain01:14:31
the abyss, but the fact is that the java script is like this01:14:34
called weak typing01:14:38
you know other names but that’s not the point01:14:40
I'll try to tell you what we have01:14:43
languages with strict typing, for example there01:14:46
pascal siplus some kind of dried and01:14:49
so on, that is, in them and for each01:14:52
you clearly set the variable to go and01:14:54
which one is she from which one on this01:14:58
something will follow the engine01:15:10
kvass machine the machine can drive if you01:15:13
you have a variable of this type01:15:16
the car means it can drive all this01:15:18
that is, what is she like from this immediately01:15:20
follows its functionality if like java01:15:23
in the script you have a line that means in this01:15:24
the lines have indexes, yes, that is, this one01:15:27
essentially the definition is that she just has01:15:29
there are indexes determined goes by type on01:15:31
she string means true juice01:15:34
in java script those are actually typing01:15:37
not persistent, that is, some we walked01:15:40
money kitty stormy different everything like that01:15:42
how to translate this from one according to the cathedral01:15:45
side weakness is why many people don’t like it01:15:47
java script especially those with strict01:15:49
languages are being transplanted, but it seems to them01:15:52
this is all terrible anarchy in fact01:15:54
when you have certain experience you01:15:55
see how much of this is too much01:15:57
interesting things Nastya just have01:15:59
it's flexible but you just need to learn with01:16:02
work with this and use it in01:16:04
your goals and01:16:05
so in fact Moscow is duck01:16:09
typing or in other words you can01:16:12
say weak what does it mean01:16:18
so I guess let's use jackets as an example01:16:22
Let's say we have some form of goal01:16:24
And01:16:26
We01:16:28
we pull it out and she gets it01:16:32
she calls to this hole in this jacket01:16:35
method of what evidence can be the quack method01:16:39
let's let her have it, that's who she is01:16:43
crack in any normal language Oleg let's say01:16:45
so it was written here in parentheses that01:16:48
pregnant doctor type way to already right in01:16:51
even compilation time is only when01:16:53
the compiler compiles this project, it is already01:16:55
sent once they run to it means so she has01:16:58
there really is a method to quack everything01:17:00
everything works great already at the stage01:17:02
compilations that are in yolks and generally not01:17:04
some error would already be visible01:17:07
couldn't call bought find another01:17:09
kind of which is not there, he would check everything01:17:13
in advance and when we call this function01:17:15
from somewhere I’ll write war there now01:17:20
where let's say I really created01:17:22
way and01:17:24
I call this function our f and01:17:29
I tell you it was in vain that they called it there01:17:31
let's call none, for example r, they passed it on01:17:35
everything is no longer the compiler of that01:17:38
same si plus plus checked it means01:17:40
here we expect a variable like yes and we01:17:43
here we are actually passing a variable01:17:45
like everything fits right01:17:47
and everything can be checked in advance even01:17:50
then the code execution stage of the java script01:17:52
this is not to be, we just call01:17:55
feature advanced something its this01:17:58
something is called kolyan in this case01:18:01
I passed it so everything works but if01:18:04
suddenly I instead01:18:06
transferred well I don’t know there is a tiger01:18:11
r2 what do you think will happen now01:18:16
edges as soon as the function starts, it will be called and01:18:19
Janoski will try to get him high01:18:22
this object has a crack, this one has it01:18:25
there is not only me, probably not even then01:18:27
an error will occur here, well in this class01:18:31
to my own described, we decide for ourselves01:18:33
what kind of thing is this? yes the tiger we can the tiger01:18:36
we can ask the wrong crack mother01:18:39
we describe this class as we want it01:18:41
haven't passed it yet, I'm still trying to understand01:18:43
just give it and then we'll call this one01:18:45
function is a problem even though the game will cause01:18:48
him the quack method because he understands that01:18:50
is manual typing no matter what01:18:54
what type of object is it important that it01:18:56
knows how to quack since he knows how to quack01:18:59
functions will make him quack and what01:19:01
sleep games dude it doesn’t matter, it’s clear01:19:04
approximately what am I talking about yes I then01:19:07
I'll stop here, we're doing the same thing01:19:10
we can if someone is already a little familiar with01:19:12
with these hashes we can here I am please01:19:14
look, I'm describing the hash, I'm not saying what it is01:19:17
this stacking hashes and this is the function01:19:20
who do that is also not an object01:19:23
ordinary and shexne yes yes he has01:19:26
elements creo que all will be called and that's it01:19:29
it almost gets to this function is trying01:19:31
there was a change create this one works01:19:33
approach although it is not an object at all01:19:35
some class is ordinary01:19:37
simple object01:19:39
chestnuts everyone knows dated so I01:19:41
use while singing01:19:43
you see, it works differently01:19:46
typing Putin and I just drove bye01:19:49
term duck typing so you like01:19:50
once again now, using an example here01:19:52
this is a duck array explain why01:19:54
street, well, that means during work, anyone01:19:58
functions we have showing let's call it01:20:01
array argument and in this array01:20:04
argument all the arguments that were01:20:06
functions are transferred, that is, look here I am01:20:08
indicated and I gave her the function itself01:20:12
actually expected but only a01:20:15
accordingly it is clear that this is it01:20:17
passed to this variable correctly here01:20:20
to the console this is a pain function to the console01:20:22
your your client and here he is aaaaand after01:20:26
it displays the length of the array01:20:29
argument not she turns out to be 2 because01:20:33
the function is passed two arguments and then01:20:35
this loop over everything01:20:37
array argument and prints everything01:20:41
get all the arguments here they are01:20:45
if they were afraid passed 5 moment they would all01:20:48
here that is, the function can receive01:20:51
access and even to those arguments of which01:20:53
it wasn't stated that way in the description01:20:56
for example it works you probably know01:20:58
there are a lot of us. min until you know this one01:21:01
the thing finds the minimum of all arguments01:21:03
you can give it as much light as you like01:21:06
all likes like this like this such functions01:21:09
you do it yourself again like this01:21:10
functions can be done but I'm not sure yet01:21:13
called the array the argument is actually an array01:21:15
in fact, this is not a Mosin, this is again in pro01:21:18
simple and who only has01:21:20
lens and only properties 012, for example,01:21:24
any array has a remember icon there01:21:27
join date methods and even these methods01:21:30
the argument will therefore cannot be called01:21:32
massively this is dishonest mass this is something01:21:35
pretending to be very simple01:21:37
array, that's why Putin says array01:21:40
that is, if you hear the word Putin01:21:41
array or something else makten01:21:44
which means, how about you, it’s not an array, it’s just01:21:46
rest in some sense behaves like01:21:48
the majority of us will still have such things01:21:50
meet in other places sometimes they01:21:52
even much more complex than the masses but01:21:55
they just pretend to be arrays so that01:21:57
you could work with him as you usually do01:21:59
work with the masses until the idea is clear01:22:05
that's good and so this thing with01:22:08
argument it always worked and this mask01:22:11
of us is another syntax01:22:14
like this, that is, we can say01:22:17
what this function can it receive01:22:20
as many arguments as you like, here I am to fight01:22:22
almost conveyed and what does this mean01:22:26
this will go here this will go here01:22:29
but these two will go here01:22:34
Yes, it’s clear, that is, you know, if the argument01:22:36
this is an array of all arguments01:22:39
then this is the excitement, this is just an array01:22:42
other arguments saw the difference here01:22:47
and this is an honest array that is not real01:22:50
pull01:22:51
so let's see, I called him01:22:53
abcd what does this function do it in01:22:56
the console is releasing the album here they are01:22:58
turn on aigul01:23:00
and then it prints the length of the other array01:23:03
here it is, these two are both here doing a cycle in01:23:07
all this element of the array breaks01:23:09
drives, they aim and so everyone understands01:23:11
what did you get here who is already overheated01:23:15
wash yourself well, hold on, so I01:23:19
I saw something good here and wanted to show it01:23:21
this is the thing and01:23:24
and someone can call her differently01:23:27
calls spread heard this word01:23:29
someone calls ellipsis someone else01:23:32
when I want to clarify a little01:23:34
so that you understand what the words mean01:23:38
ellipsis is actually the name01:23:40
this symbol that I highlighted01:23:42
ellipsis then he is exactly the same as01:23:45
for example, look at this!01:23:49
symbol name ! but its role is java01:23:52
in the script the logical logic is not correct so here it is01:23:56
this symbol that you are behind the stage of liksys01:23:58
but its role in this case is spread01:24:01
operator that is everything about he forces01:24:04
some things01:24:05
decompose inside the array and for01:24:08
that's why it's called a spread, that is, a spectacle01:24:12
name series symbols perform a role01:24:14
so 2 names test two names in01:24:16
in different places this is the problem that01:24:18
there are two of us out of spite what day01:24:20
so good now look I will01:24:23
show examples of what a function is01:24:26
one of the data types is the same as integer01:24:28
number string and so on one of01:24:31
the most important features of java script are one01:24:32
one of the most01:24:35
can I say this so we have01:24:38
faction data type accordingly is01:24:40
bank type variables01:24:43
so look, he describes it, I’ll draw it01:24:47
that is, normative01:25:01
I wanted this function so what does it do?01:25:06
so I call it accordingly this is what01:25:08
she does it, but I typed into the console01:25:10
of f1 remember that year determine the type01:25:13
its argument f1 this function that is01:25:16
f 1 is not any specific01:25:19
strange design it's the same01:25:21
the expression is like any other, that is01:25:24
where do I find out you found out that I personally can01:25:27
create some variable name i01:25:29
put f1 got fancho because f101:25:32
this is the variable in which the function lies01:25:36
in some, change mode is an integer value01:25:38
other functions of these something else here01:25:42
now look a little further I01:25:44
declared function f 2 and now01:25:46
ordinary variable f2 lev01:25:50
the variable is assigned to it 2 now I have01:25:54
the topic of this variable and in this variable01:25:57
the same function of the 1st floor actually01:26:02
in fact, these are links to one function, but we01:26:05
the term is dry until I wanted it, I think01:26:07
I'll tell you and I can call this01:26:10
so these are two brackets these are01:26:13
operation from a function call operation01:26:17
remember the plus sign is a binary plus01:26:19
parentheses are a function call operation01:26:22
you remember we have the concept of prefix01:26:25
them postfix on the operation before the bracket01:26:27
what kind of operation is this01:26:30
postfix on I and ours is written after01:26:32
operand yes, that is, the operand of the operation is here01:26:36
this is a function call, that is01:26:38
$ 2 brackets should be any01:26:41
function expression in this case01:26:44
here is a variable of type function and here it is01:26:46
beautiful called the street yes here I am01:26:48
I'm checking secretly from this f2 reef, it's the same01:26:51
I get hanshi between r yard and f2 no01:26:55
no difference it's the same thing01:26:58
it turns out that I can do it like this01:26:59
I can write a function like this, well01:27:01
for duplicating her description we can say01:27:03
result01:27:05
let's go a little further, I describe the function01:27:10
f 3 so so I'd like to be here01:27:16
I forgot what the trick is here01:27:19
I remembered everything, look still then01:27:23
I described the function using function like this01:27:27
I'm telling you how it would turn out01:27:29
variable f 2 function type and now I01:27:31
I even explicitly say that this is a variable01:27:33
see variable f3 and what I have01:27:37
welding description of an unnamed function01:27:40
notice after filing no01:27:42
here is the result exactly the same, that is, I'm in01:27:45
f3 put the function now repeat01:27:49
function here I called it here it is01:27:51
it worked, so I checked it secretly01:27:53
studied, yes, that is, between this01:27:58
description and such a description almost01:28:00
there is no difference there is very subtle01:28:02
the difference to the lower levels can01:28:03
ignore 2 ways to develop one and01:28:06
Same01:28:07
here is finally the last option too01:28:09
just take a look at the argument01:28:12
variable in variable in 4 lies01:28:14
function receiving one argument here I am01:28:17
called this function passed an argument and01:28:20
so she brought out what she wants to show01:28:23
so you feel that the functions are simple01:28:26
Saint Arnaud yes we can rearrange them01:28:28
from date variables baby thread01:28:30
piece01:28:32
so good now they were traditional01:28:35
functions according to the classic ones that were01:28:37
the very birth of Dzhurovski in Moscow in01:28:40
honor we have a new syntax01:28:42
functions that the hare functions with he more01:28:45
compact and has a couple of new01:28:47
interesting features you already understand what you need01:28:50
will reconsider01:28:54
who has time01:29:04
as long as you are sure01:29:09
a little bit different from different01:29:12
written all are all similar you are right if u01:29:14
Do you have programming experience in another area?01:29:15
language you have a lot of things we are here on the floor here01:29:18
okie means if anyone wants a video01:29:20
write to me please give me a video01:29:22
I will need your item because01:29:26
there is a free right to provide so01:29:29
look at the syntax01:29:31
it is through the bar that the name is of war01:29:35
functions equal to and before I show you01:29:38
the last example was here01:29:39
function arguments and body are written01:29:43
look here what01:29:45
arguments in parentheses then icon right01:29:48
arrows to the right and then some01:29:51
expression which is the result01:29:53
calculation results works and functions01:29:55
that is, a more compact option01:29:57
Please note I am not showing how here yet01:29:59
let the body be described for now01:30:01
it is assumed that most functions01:30:03
just return one value01:30:06
and the calculated map for example I will be this01:30:08
what the calculated function showed01:30:10
number of days in a year remember she01:30:12
received an argument based on it01:30:15
simple calculations and returned 3536 from this01:30:18
all logic accordingly the majority01:30:21
functions is exactly what they do, they simply01:30:23
return some calculation based on01:30:26
I show you my own arguments01:30:28
this option will come a little later01:30:30
I’ll show you more generally, so look, let’s say01:30:34
we want to write a very important function01:30:36
who will find out any01:30:39
the specified number of hours, that is, we01:30:42
we will give 5 hours and she will return how much in01:30:45
them minutes, that is, multiply by 60 to01:30:48
the brilliant idea is clear01:30:50
just to show how it works01:30:52
The functions of the arrow cannot be described yet01:30:54
there are, please note, no curly braces01:30:56
no reason just after the arrow01:31:00
we write down the expression01:31:02
that is, as if you think that01:31:04
wrote a carriage written and then this01:31:07
you just don’t have to write this expression and01:31:12
now I'm looking at the console is important in01:31:14
five hours how many minutes do I call the function01:31:17
get me persons here she is and 5 that is01:31:21
meaning for this formal01:31:23
moment, the result increases accordingly01:31:26
throughout the entire function this is a finite number01:31:28
multiplied by 5 equals 60, that is01:31:30
this expression is equal to01:31:31
63 here it is so you saw this syntax01:31:36
Yes01:31:37
it is not the most general, it is the shortest01:31:40
in general not now a little forward then01:31:43
there is a return but there are no curly ones here01:31:44
no brackets this is important now I'm here01:31:47
the argument half hour rocks did not take into account01:31:51
parentheses if the argument is exactly 101:31:54
you don’t even have to write them, that is01:31:56
It turns out that in general these are the records01:31:58
I will often use this entry in general01:32:01
its functions are shown by arrows01:32:03
it's a brilliant idea, that's how I already am01:32:06
today told a lot about the functions of this one01:32:08
from data types or will often be01:32:10
deal with what to pass to the function01:32:12
as an argument you probably all01:32:16
saw foreach take its array . for01:32:18
which array . map everyone is Khan's friend01:32:21
you pass web for each as01:32:23
function arguments is true if and01:32:26
write in the form of an arrow record01:32:28
it turns out very simple and clear to you01:32:30
you don't even need to describe it separately01:32:32
we really need it together01:32:36
so it turns out compact, that’s it01:32:40
so you can remove the brackets then it works01:32:43
here's a simple recording exactly the same01:32:44
works but but if there is more than one argument01:32:47
0 or two or three then parentheses are needed01:32:51
be sure to install it then01:32:53
if suddenly the arrow function should not01:32:57
just calculate the expression like here01:32:59
said, but do something anyway01:33:01
some kind of logic by the Scythians there and so on01:33:03
then let's move on to something more complex01:33:05
option after the arrow you can put01:33:09
curly braces and internal01:33:11
write down anything like this you do01:33:13
so far diwali in the usual function that is01:33:15
look at the get top 2 function01:33:19
receives a formal argument with01:33:21
and does the following because they are01:33:25
curly braces means you can inside01:33:28
write down whatever you want like you do01:33:30
done before with date return statements01:33:32
everything works as before, it turns out that01:33:34
this is the recording, it's not much better01:33:37
than what was fudge is simply not here01:33:39
the words fudge there is the word fountain and01:33:42
there is a curly arrow arrow here01:33:43
that's all and the whole difference turns out to be01:33:46
records01:33:47
therefore there are no big advantages, but01:33:50
arrow functions there are other miracles I01:33:52
then they stopped it and01:33:56
there is no argument arrest operator working01:34:00
this one with an ellipsis but the argument is not01:34:02
work today is almost never01:34:05
don't use arguments because I01:34:07
then I’ll show you the slides and show you examples01:34:09
that there really are some things01:34:11
which sharply slow down the speed01:34:14
so something becomes a problem01:34:16
for example, 1050 times and strangely enough01:34:20
using this particular array01:34:22
argument slows down the code immediately because01:34:25
which, in essence, its use does not provide01:34:28
browser to apply optimization techniques01:34:31
code01:34:32
T-shirt so that the browser can01:34:34
the code needs to be optimized so that it01:34:36
used and followed certain01:34:38
rules and one of these rules is not01:34:40
used by two me then that's all01:34:42
I'll show you that is, don't worry yet, I'll01:34:44
I’m just explaining that they didn’t remove it in vain01:34:46
come to their senses they removed him from support01:34:49
rs3 functions exactly how to speed up to01:34:52
say use the rest operator in this01:34:54
the script has arrow functions there is a risk01:34:56
you don't need to think through the operator at all01:35:00
good that01:35:03
I haven't said anything good about the dots yet01:35:06
, said so so01:35:10
yes now look01:35:16
small simple example01:35:21
let's say we have an arrow function there01:35:24
f equals important to us on let's say without01:35:27
arguments and she should if she should01:35:31
was just to return and then let’s say she01:35:33
gets it for what the mother can do for 501:35:35
That's all I wrote, so everything works01:35:38
now let's assume that she01:35:40
should return a hash or an object whose01:35:44
one of the properties is equal to 5, that is, for example01:35:46
its task is to return the next thing01:35:50
what was that is like this01:35:55
that is, I can try here like this01:35:59
I want this function to return to you01:36:07
I understand the idea yes01:36:09
to01:36:11
trigger line01:36:13
I put two brackets01:36:17
curly braces meant that I would01:36:19
Here write the body functions are normal01:36:22
in poetry and so on and I will clearly write in a row01:36:24
I understand the problem, yes, that is, because01:36:27
curly braces like many others01:36:28
just5 characters multiple roles curly01:36:31
the brackets are part of the hash literal or01:36:34
object curly braces is a selection01:36:37
code block in myths in function loops01:36:40
and so on, yes they have three roles but01:36:42
It turns out that these videos will interfere with eating01:36:45
so need some01:36:47
state01:36:50
quotes reveal stage01:36:54
if I put pebbles here and01:36:57
xcode01:36:59
what else and cattle and brackets why and only01:37:04
parentheses its the rock of today's show01:37:06
We put brackets in a circle like this01:37:10
seeing the parentheses java swing understands everything01:37:13
the expression began and everything was already in good spirits01:37:16
expressions please want figures01:37:18
buy what you want, all the main thing is that he01:37:20
I realized that there is no code block yes01:37:26
no Yes01:37:29
don't understand, that is, look, if I01:37:32
I’ll write it so it turns out that it’s a java script01:37:35
understands that the code block has started01:37:37
there is this block you need to complete01:37:41
here they wrote oao x java drain let's do it01:37:45
this is the expression01:37:46
what is it equal to01:37:50
hash is not the result of errors and expression01:37:54
I'm hooked meaning but this is where01:37:58
the function will lead to antifa no after all01:38:01
our code block means you must01:38:03
via return geoff number value and you01:38:06
he doesn't get it back01:38:07
you see, they don’t help like that01:38:12
Fine01:38:17
yes, so now look at us and about01:38:21
rising description good interesting topics01:38:23
yes this is the account to enjoy01:38:32
still saved the slides for the same one01:38:33
topic, that is, the same topic about01:38:35
functions I show some tricks01:38:37
which can be used01:38:39
that is, let's say the matrix is our task01:38:42
write an alarm function01:38:45
we can do this function we can do this function01:38:48
call and give her a message that01:38:51
need to show the person before the typical time01:38:53
for work or we can call you without01:38:57
arguments and then it should show01:38:59
some standard message for example01:39:01
the rise is so clear the idea, let's do it01:39:04
Let's look at the simplest option first01:39:05
that is, I call it and pass the argument01:39:08
this is the function this is its formal01:39:10
document accordingly this line01:39:11
this one formally goes here01:39:14
don't look yet just trigger01:39:16
console lesson and01:39:18
time to get to work okay yeah okay now01:39:21
look we call it without arguments01:39:24
means the place will be equal to01:39:29
undefined is correct now look what01:39:31
does this line look down or01:39:34
you can go through this today01:39:38
topic, that is, the result of what will happen in01:39:40
rise to that is, look if in a month01:39:44
there was something like this line then01:39:46
it may remain true that but if places01:39:51
history, that is, any that is given01:39:53
minced meat then instead of the word customization01:39:57
caught the logic01:39:59
this is one of those uses01:40:02
that abbreviated logical calculation01:40:04
show the fish expressions, that is, by01:40:06
essentially this line means I want01:40:08
so that if there is a place and it becomes equal01:40:11
climb01:40:12
accordingly this line will come out exactly01:40:14
rise and this is also what the rise looks like01:40:18
any empty value x pull something else01:40:21
then she will lead because they will01:40:22
show your let down, you see01:40:24
first breakup time to go to work then two01:40:26
three times so it’s clear how it worked01:40:30
so let's move on now01:40:32
with default value second option01:40:36
look, I describe the function, I say that01:40:38
its moment of places and by default it is equal to01:40:41
then also a good good way yes I01:40:44
I call her with the dictionary, it's time to go to work01:40:46
accordingly, this value is no01:40:48
doesn’t play a role and keep silent or01:40:50
the console displays the message it's time to go to work01:40:52
I call without arguments01:40:55
triggered to remain silent and flax and meaning and01:40:57
so in the console there will be exactly the rise I01:41:01
calling with an empty line01:41:04
what happens01:41:07
empty line I will remain that is01:41:10
the message will be empty because since I01:41:12
conveyed something to keep silent other meaning not01:41:15
it works I passed the pieces01:41:18
accordingly, look at three different01:41:20
messages it's time to go to work getting up empty01:41:22
reported01:41:25
so let's move on now the topic is interesting01:41:28
called rise description it's still the same01:41:31
the best thing to do is to cave in after talking for now01:41:33
this scope goes through and so on01:41:35
further, that is, look at the console01:41:38
I output the variable b is equal to01:41:41
but note that there is no variable in I yet01:41:44
I haven't described it yet01:41:47
then I write barbarian blocked so and then01:41:52
once again I point out what is equal to you and that is01:41:54
look what the trick is in the ad01:41:57
variables made specifically through the bar are not01:42:01
summer horst namely through war are divided01:42:03
essentially two parts war in it is equal to 5 g01:42:08
equals 5 she stayed here01:42:10
accident in [ __ ] up here01:42:12
this is called a rise, why a rise01:42:16
understood why it rose and why it died01:42:18
exactly the description because this is it01:42:21
variable declaration with assignment01:42:24
assignment here and there will be a declaration01:42:26
lotus page variable at the beginning01:42:30
the beginning of the scope, that is, this01:42:31
case at the very beginning of the script, well01:42:34
it works, this is also a strange thing01:42:37
that's why it doesn't work like that until 1 steals01:42:40
that's exactly how it works, that is01:42:41
will be displayed01:42:45
if you just declared a variable in we01:42:47
I can’t do anything yet means not and if any01:42:50
and here there are 5, that is, in the console01:42:53
will rest no and 501:42:57
so we understood that it’s in English01:43:00
called hosting the term is so important01:43:04
now watch the trail01:43:07
so I declare a variable after years and01:43:10
I'm trying to get to this ad01:43:14
tell her what01:43:16
mistake yes because at this moment this01:43:18
there is no variable yes this is also one of01:43:22
count the jambs that were01:43:23
corrected version and to Moscow 601:43:25
Well, you must agree that it’s a strange game01:43:28
behavior is addressed to change before it01:43:30
creation she already action meaning no01:43:32
corr it’s unclear there01:43:36
here is a description of the constant, the same as years then01:43:39
there is karst work as well as years in this01:43:41
sense there will be mistakes01:43:44
now01:43:47
we just learned the description of the function01:43:49
description of functions rather than01:43:52
the situation is exactly the same, that is01:43:54
because this is again so much description01:43:57
function it rises to the beginning01:44:00
scope is one thing to remember01:44:03
assigning another case by description then01:44:05
is that you write function here01:44:07
what do you write it here makes a difference01:44:09
no none anyway all functions wherever01:44:12
they were not described in the code, consider that01:44:15
they were described at the very beginning01:44:17
Accordingly, the function can be called before01:44:20
how the analysis is01:44:23
work we immediately see some kind of game01:44:28
like this and now look at me01:44:32
I describe I described the function now ordinary01:44:34
as usual with the function keyword01:44:36
now I describe war ff park differently01:44:40
f equals minced meat we've already seen this one01:44:42
design yes here nameless01:44:45
here is one and one of those places where the difference01:44:48
the behavior will be the same as the description01:44:51
or copper ff and assigning a value to it01:44:54
so you already know that war ff will work01:44:58
to the beginning and here is the assignment itself01:45:01
it will only work at this very moment01:45:03
so here's what you see01:45:06
anda file and here is what will be displayed01:45:10
you know what to stand out01:45:12
if I write the variable f f is equal to a in01:45:16
this variable, as you know, already lies01:45:18
functions that you are the text itself is literally the text01:45:22
functions and respectively can be called01:45:26
see interpolate here is the text of everything01:45:29
I'll take you away01:45:33
I mean, look when I said that01:45:35
here they will come I said on the previous slide01:45:37
think that this function is declared in01:45:39
at the very beginning of the year it’s actually the same01:45:42
the same thing works and here is this function01:45:45
these are the ones I’ll highlight now, it’s announced01:45:47
at the very beginning of the year it’s just that no one is there yet01:45:50
did not assign variable f dream means that01:45:54
there is a java script created at the very beginning01:45:56
year variable ef ef equal to mdf and here01:45:59
this nameless function but we haven’t yet01:46:01
we can call I don't have a name and only01:46:03
this is the moment when we got here01:46:05
and this nameless function went into this01:46:08
variable therefore it became possible and if we01:46:10
let's set a strict regime01:46:12
that means not everything will work the same way01:46:14
yes here he is here yes no problem with01:46:16
this is not but this is like behavior01:46:19
strange but it's not fraught with problems you01:46:21
you just have to understand it and that’s it01:46:23
what's inside the function without war01:46:26
variables are described globally01:46:27
really dangerous middle01:46:31
ran so far so that means he's here01:46:35
ok not said yet yes not shown here01:46:39
one very creepy hello indeed01:46:42
really look01:46:44
show this01:46:48
here we have some kind of function01:46:53
called f01:46:55
well, you know that for example I’m here01:46:58
could low city tournament there 5 and01:47:02
anything01:47:03
if I write a variable right here there01:47:07
bar army 5 she acts remember inside01:47:10
the whole function because they have a van01:47:12
scope of any01:47:14
if I describe or in years01:47:17
it will only take effect inside the div01:47:20
because jump and the next year01:47:22
lining but what if I announce here01:47:26
function01:47:27
any way f.f. And01:47:32
This is where I don’t make you guess what01:47:36
will be because this is the behavior in01:47:38
standard are not described and therefore each01:47:41
browse who realized it for what purpose01:47:43
works unpredictably yes that is where01:47:46
it will be visible here it will be visible in01:47:48
at what point will she start doing nothing at all?01:47:50
it’s clear that’s why this behavior01:47:52
through the narrow who calls ours that is01:47:55
description of the function days in the hands of some01:47:58
Abram visibility block other code01:48:00
block here it will be01:48:03
but no one is stopping you from doing it here01:48:07
By01:48:12
Fine01:48:16
a lot of details and probably immediately in01:48:19
the picture doesn't add up much further01:48:21
we report a lot of things and these are these01:48:23
mosaic details that will be available01:48:25
I somehow carried the foundations to collect01:48:27
they were going to masterfully they were going to anyone01:48:30
everything is going01:48:32
well you are animals01:48:38
ok yeah I hope it all comes together01:48:41
that's quite a lot for today01:48:43
In general, it was the small parts that were kicked out01:48:47
you understand and know what you need it for01:48:49
java script and you understand what the language is01:48:51
java script and we will be finished very soon01:48:53
studying it is enough for about 2 years01:48:56
classes then we actually start01:48:58
study the browser that is those possibilities01:49:01
who [ __ ] hard are provided with01:49:03
hand browsers how to draw how01:49:05
how to work with the heart01:49:07
steel, that is, something that is not01:49:09
the language of java scripts in general, but what01:49:11
is what it is called in other languages01:49:13
runtime caught yes you are something separate01:49:15
that the next one is provided01:49:17
layer that's why now I would say01:49:20
so many technical details01:49:22
but they will soon end and go much further01:49:24
more interesting so and so I wrote before01:49:28
good night with you01:49:30
now look at the term the term is very01:49:35
I’ll write him an important term now01:49:37
no Slavin01:49:39
called a pure function01:49:45
And01:49:46
to know something like that01:49:51
appointment01:49:54
of this disc, yes, look like this01:49:58
so it was clear that this was a pure function01:50:01
function that only works with01:50:03
with your arguments01:50:04
that is, in brackets it does not refer to01:50:07
something for no global changes01:50:09
and it doesn’t fit into the browser pages01:50:12
she only works with her own01:50:14
arguments01:50:16
function a or dobrev who receives01:50:20
argument and I for example does return01:50:23
on all can on 5 this is a pure function01:50:28
it only works with its own documents01:50:29
and that's it, of course she can cause it01:50:32
mathematical rounding please01:50:34
maybe something like that but if I have01:50:37
there was a global variable g by01:50:40
functions should not be handled more precisely01:50:43
technically she can but then she no longer01:50:45
I'm just trying to understand right now01:50:47
distribute and what is pure because01:50:50
I'll be in some homework01:50:52
clearly demand a clean street here01:50:55
why is this important the thing is that in01:50:59
the next year after the development01:51:02
the next stage is knowledge about01:51:04
wine01:51:07
I wanted to talk a little about other testing01:51:10
that is, you usually write the test yourself01:51:13
tests, of course there are different tests01:51:16
unit tests there manual testing is important01:51:18
but your programmer's task will be01:51:20
write unit tests, that is, write tests01:51:22
write your own code another year01:51:25
which tests previously written code01:51:27
try to call it and check it done01:51:31
is it what you need if you write clean01:51:34
their functions are easy to test if you01:51:37
write dirty functions before such a term01:51:39
no, well, as is clear by analogy with01:51:41
numerically should look at testing them01:51:43
very difficult because their result01:51:46
calculation depends not only on the hands of01:51:48
cops and something else and you will have to01:51:51
testing not only a function is a task01:51:53
has testing test uniq then01:51:55
there is a small piece of code for example01:51:57
function and if your function is unclean01:51:59
you have to test everything at once with01:52:03
all global variables with01:52:04
somehow there and yak themselves and01:52:06
web pages and so on this is 100 times01:52:08
it's harder when you write purely and very01:52:10
it’s just that each purely function is put01:52:12
separately because it works nothing01:52:14
don't depend on01:52:16
there are so many of them and housing the result depends01:52:18
only from her arguments the idea is clear01:52:20
remember this term and I'll talk about it more01:52:24
Of course I won’t tell you, but always when01:52:26
just maybe you should try01:52:28
write exactly clean even if it’s obvious01:52:31
it’s not said better write clean ones for example01:52:34
if the task is to ask01:52:36
I don’t know the user there, the odds01:52:39
Corgiga type of quadratic equation01:52:41
fighters and find the roots and everything using code01:52:47
it means you understand that something will have to happen01:52:50
it cannot be asked by the user01:52:52
make a pure function right means y01:52:54
you should have a separate pure function01:52:56
which you pass on and the fighters she01:52:59
rotates the roots and separates from which01:53:01
asks the user for something01:53:03
calls this pure function i.e.01:53:05
you break down the functionality into pure and01:53:06
unclean pure will be easy to test01:53:09
they are usually clean, very easy to ask01:53:11
the user and you are to the credit of everything therefore01:53:14
it was tested for yes you see01:53:16
try so I will of course talk about it01:53:18
it's not for us to say01:53:20
so so good01:53:25
Now the scary thing is recursion01:53:29
what does this kind of love mean?01:53:33
yes, why01:53:38
then okay let's see here we have01:53:41
there is a terrible thing, recursion, the trick is01:53:44
that a function can call itself01:53:46
very useful and many things can be done01:53:49
made only this way let's01:53:51
first let's look at the non-recursive normal one01:53:55
function to calculate factorial who01:53:58
remember what repetition is01:53:59
earthly everyone is even correct I'm not01:54:02
I want to scare you, mathematics will not be01:54:04
a lot yes but sometimes just small01:54:07
like this, come somewhere like this, I’ll be like this01:54:09
little things, I think I’ll explain everything01:54:11
that is, it is not easy and the mathematical basis01:54:13
you don't need factorial anyway01:54:15
the product of all numbers from 1 to for example01:54:18
5 factorial01:54:21
envious mathematician is one01:54:26
everyone just let's try and that's it01:54:30
I describe the factorial function it gets01:54:33
this is the most 501:54:36
volume cycle under it from 2 to 5 why from 201:54:42
to 1 there is no point in pressing 15 just01:54:45
faster yes from 2 to 5 5 and this one here01:54:49
directly multiply by 2 by 3 4 by 5 and01:54:52
return it's all easy everything is clear yes01:54:57
fill in here will not come out on if you are a loop01:54:59
exactly about n inclusive and they are trying01:55:02
do as01:55:05
and you saw exactly yes because I01:55:08
sometimes now she was 5 me before him and01:55:10
should only come with elections01:55:12
here I call the function using 12001:55:16
now let's try to write01:55:17
recursive01:55:19
function that is what I want as for01:55:22
I started to want to show some idea of flying01:55:26
look at this, here is the 5 factorial and here01:55:29
this is it01:55:31
that is, the factorial volume of this is so true01:55:34
look from here as beautiful as possible01:55:37
see what the factorial of pizza is01:55:41
factorial 4 and01:55:43
which multiplied by 5 so everyone saw it01:55:47
yes, that is, repeated for any number01:55:51
this is the number itself multiplied by the factorial of 301:55:54
what do you think creatures01:55:58
factorial 5 is 5 times 401:56:01
factorial 4 urgency is 4 times01:56:04
factorial 3 and so on yes it is possible01:56:06
imagine it or so well01:56:08
let's just imagine this for now and01:56:10
so nasturtium fact 2 we volunteered it01:56:13
five don't look at it yet, what is she01:56:16
does it return 5 times and01:56:19
call yourself for the fact for calculation01:56:21
factorial 4 and how does she calculate the factorial01:56:24
4 it returns 4 times the factorial01:56:27
3 how to calculate 3 of 3 is 3 multiplied01:56:32
to factorial 2 factorial 2 is 201:56:35
multiply by factorial 1 and here is the factorial01:56:38
1 there and right here and sewed up we are preparing a kid01:56:41
you don't have to stop at she either01:56:44
nano-ram will start to press -1 and then a01:56:47
that's why it's better that I'm right here01:56:49
this pastor01:56:51
[music]01:56:56
that is, in any recursive function01:56:59
besides cutting herself out for sure01:57:02
there will be some condition somewhere01:57:04
stops this endless challenge and then01:57:07
is she able to calculate factorial 501:57:09
caused herself for 4 she did for herself01:57:11
for three and so on there must be somewhere01:57:13
the end is like this and in which01:57:16
you return a value without recursion01:57:18
call ready something like that, I hope01:57:22
you have roughly what we want01:57:23
do this I called this function and got it01:57:25
120 what's good about this way01:57:31
she's disgusting01:57:32
look, but what's the point of these sets?01:57:37
why is this better than not at all than us I her01:57:42
artificially written in order to01:57:44
show factorial 1 is good only because01:57:45
that it’s easy to show how it works01:57:47
how recursion works all this code01:57:51
it is much clearer and much faster and01:57:54
he doesn't waste a finger and every call01:57:57
functions then the consumption of a small piece01:57:58
memory some know the words stack01:58:00
stack overflow have you heard of these?01:58:03
Accordingly, it’s worth calling like this01:58:06
We have an example of this function with argument 100001:58:08
the world get a console error01:58:10
crowded because she's herself01:58:12
called him a thousand times and every time she called him01:58:15
every time she calls herself01:58:17
end-to-end information is delayed so here it is01:58:19
when I'm done I need to come back01:58:20
back here is the return information yes01:58:23
it doesn't take shape too soon01:58:24
or late the old man is overflowing therefore01:58:27
This function is no good except01:58:29
that it’s easy to feel what it’s like01:58:35
no good cheek very much and you will be like01:58:40
since homework on recursion I think01:58:43
that you will understand well why she is there01:58:45
needed but we often have different01:58:48
complex structured data01:58:50
unpredictable nesting for example01:58:52
imagine tags on a web page with us01:58:54
there is a body during the day 3 divas in one case 2 p in01:58:58
in another it’s 8p and in some there’s a bunch more01:59:00
something yes and we need to get around it all01:59:03
there is, for example, collecting all the texts on01:59:05
pages something like that01:59:06
accordingly, it is recursion that will allow01:59:08
do this, that is, what is the amount equal to01:59:10
of all texts on the pages this means01:59:12
you need to take an empty variable and pass with01:59:14
cycle through all this first level and01:59:17
call the same background for her to come in01:59:20
above these 2 levels and how is she there01:59:23
she works, she calls herself what to go through01:59:25
third level tags yes you understand01:59:27
that's when she gets to this point01:59:30
which no longer has subsidiary clients01:59:32
there is just text for example span only01:59:34
then the value of all of them is returned01:59:36
they're all coming back01:59:39
there are many examples of very good examples and01:59:42
Believe me, it’s practically super useful01:59:44
there just if I explain01:59:47
in a real example you won't understand anything01:59:49
those who don’t understand yet, understand this01:59:52
quality is still easy to discuss, but01:59:54
this is something very easy to show like this01:59:56
works01:59:57
I hope you understand this about01:59:59
let's work it out in homework like I did02:00:01
already told me earlier now Karl is here02:00:05
minibus now you understand what to do02:00:07
to understand recursion you need to understand and02:00:12
so good it means look you and I02:00:15
we've studied recursion, you and I are left with02:00:17
very little time and it’s time for us02:00:20
then watch homework02:00:25
review and clarify promotions02:00:31
yes and02:00:33
smokes in02:00:37
let's move on to the topic and02:00:40
remind me too, I don’t understand, we have homemade02:00:43
task from02:00:44
us in02:00:46
personal account contains face-to-face materials02:00:49
lesson slides and web version working02:00:51
notebook for now paper work02:00:53
the notebook has not yet been given to you next time02:00:55
they will issue it once, but in this working version02:00:58
notebooks have a topic n.a. homework02:01:00
here it will actually contain all 10002:01:03
homemade creator and now I can give02:01:05
the first 2, that is, you have gone through enough02:01:07
material here is this task questionnaire who02:01:10
was on a course on it alone, you look alike and02:01:12
the task is the head here just a little bit02:01:14
width so let's look at it and02:01:17
so your task is to ask the user02:01:20
his phylla three separately three components02:01:23
Full Name02:01:25
age and gender age again through02:01:27
against so02:01:29
do not forget that it will be possible to lead to02:01:32
number of fingers demand return juice and floor02:01:34
through confirm scary I'm returning home02:01:37
true stuffing and then we use the alert operator02:01:39
we issue this anchor here it's all02:01:43
understandable years understandable age days this02:01:46
just 365 higher in age, that is02:01:48
they don't think about leap days in five02:01:51
years old you will understand here what if02:01:53
forgot to convert age to number02:01:55
that is, it turns out 20502:01:59
gender is clear age you are retired02:02:03
it is necessary that men and women have02:02:05
different retirement ages any02:02:07
for example, a 55-year-old woman retires02:02:10
men 60 for example ok yes here I am02:02:14
there will be other requirements for02:02:17
execution even if someone did it02:02:18
photo 1 task I can even do it02:02:21
try to send again mine is already there02:02:22
completely different comments and well here02:02:25
you have to work what else is important here02:02:28
look there must be control02:02:30
correctness according to 10th dan, that is, for example02:02:34
surname first name patronymic should not be02:02:37
empty if a person will be success we02:02:39
just ask again you force02:02:41
introduce him until he sees02:02:44
Now, if a person used age as02:02:47
what figure are you forcing him to take again?02:02:50
enter age you can say something beautiful02:02:52
message like enter age there so02:02:54
it consisted of such-and-such and such-and-such, but can you02:02:56
he’s just asking again, but it doesn’t matter what’s important02:02:58
what do you force together?02:03:01
so actually yeah that's all02:03:04
all this is introduced wave by one operator02:03:07
couples that is, don’t try to write a lot02:03:09
art and consider different options and02:03:11
male female yes no and so on 1 Olya02:03:13
carries out all the troubles of arranging02:03:15
use string templates for whom02:03:18
interesting to practice just good02:03:19
example you can collect it via02:03:22
pluses how to paint so is it clear02:03:25
the task means what I immediately paid attention to02:03:28
attention02:03:29
you understand that you have to02:03:31
convert restaurateur data types02:03:33
number at least do it in one02:03:35
place if you have this several times02:03:38
I will make the sound you will need02:03:40
redo because the data must02:03:44
each one is an explicit conversion to02:03:47
amp parsing and so on it requires02:03:49
some time to complete and02:03:52
It’s clear that if you write there many times02:03:54
in the questionnaire, of course, it doesn’t matter, but the muscles02:03:56
preparing for the combat year before early or02:03:58
it's too late you'll have to commit to a serious project02:04:00
where no one will allow you once desperately02:04:02
just out of the blue this one02:04:04
nonsense02:04:05
it should be done in one place and in02:04:07
in many cases implicit02:04:09
transformation for example if you have age in the form of a string02:04:12
you it in years you you can multiply by02:04:15
365 and it will work but under the hood there will be02:04:18
implicit conversion yes that is02:04:20
remember multiply converts a string to02:04:22
number ak5 waste of time besides02:04:25
since she's not overtly cold02:04:27
makes you not think about it and you02:04:30
you may not notice that she is on02:04:33
actually exist, that is, not realize02:04:34
what is sooner or later then this02:04:36
somewhere someday it will shoot you will forget02:04:38
What's really in this change?02:04:40
string not hours until long then fold02:04:42
didn't notice and are lazy the worst thing is02:04:45
you guys were such smart guys and wrote the code later02:04:47
you plus 500 in years and fall on02:04:49
she came to another post of yours02:04:51
fresh man and brin he edits the code02:04:54
and everything falls apart against everything being right02:04:56
does but in fact you just forgot02:04:57
convert to a number therefore if you02:05:00
need age in the form of a number and comes in02:05:02
as a string you should get the number 802:05:04
as soon as he arrived right away02:05:07
put it in the number of everything that no one has02:05:10
who didn't even have a chance to work with02:05:11
line until the logic is clear02:05:14
so everyone understands02:05:17
explained and now the second task is just02:05:20
look at this course02:05:23
such a wonderful array02:05:25
we need to write a function that02:05:27
called there we can stick it to her02:05:30
convey such an array of people and02:05:33
she must find the sum of all numbers02:05:37
the idea is clear, so without recursion the traveler from02:05:40
everyone understands and because look02:05:42
it turns out in an array and there are numbers and there are02:05:45
you need arrays in which, again, from the number02:05:47
and for arrays and nesting level02:05:49
unpredictable somewhere one dito2 somewhere02:05:52
302:05:54
this is exactly the sum of the numbers of this02:05:56
array is 50 but your function should02:05:59
work with any available array02:06:01
whatever I predicted, do it02:06:04
please use recursion02:06:06
some are especially cunning, I immediately know that02:06:09
mind by force with, for example, the flat method which02:06:11
allows you to line everything up in the update we02:06:13
so on but we are doing this task02:06:15
because we need to find the sum02:06:16
number in the array we don't need it we need it02:06:19
pump recursions therefore precisely through02:06:21
river all these okay that's who is enough02:06:25
finishes homework early02:06:28
gets additionally ask02:06:30
additional and02:06:32
the family will not find it more difficult for him02:06:36
in short, additionally done by02:06:38
in fact, everything is done according to your wishes02:06:40
I don't force anyone to do anything they want02:06:42
homework and not necessarily them02:06:44
do it before the next lesson if02:06:46
for example, there is some kind of blockage on you there02:06:48
work or somewhere else you can postpone02:06:50
for a while there is nothing with lacie but02:06:52
then finally you can either not have them at all02:06:55
do but it’s clear that it’s on defense02:06:57
graduation projects if I see that02:06:58
the man didn't do his homework02:07:00
brought the project to understand it well02:07:03
calling it that way is why it’s still not up to02:07:06
try to do them, that's all02:07:09
I understand everything then classes for today02:07:12
finished02:07:14
questions at your disposal02:07:19
[music]02:07:22
confirm02:07:24
it’s clear from the best Russian code no no02:07:27
no conveyor and to confirm there02:07:29
the buttons are bad and canceling it with an enzyme02:07:32
I'm driving through the forts and what didn't push02:07:34
it will work out02:07:36
ladies, it is advisable to write for example if02:07:39
male click ok alaska female02:07:42
click cancel because02:07:44
what is your gender and cancellation02:07:49
regarding 2 it will be possible for the masses02:07:53
you think to put only from a blank slate02:07:55
that only numbers now we are now we are not02:07:58
I haven’t refuted the stability of the code about this02:08:00
and there is correctness and so on, namely02:08:02
pump up the rhyme, okDescription:
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