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Russian
00:00:00
Welcome to the Python course for00:00:02
beginners in this course I will teach you00:00:05
the key functions of python which is most00:00:07
often used in real projects and00:00:09
we will cover the following topics basic00:00:12
types such as strings or integers00:00:14
container types such as lists or00:00:17
dictionaries assigning values to variables00:00:19
converting the meaning of different types00:00:21
logical operators and00:00:24
comparison operators conditional statements Elos00:00:27
functions loops and string formatting00:00:29
Let's get started and First you need to00:00:32
check if python is installed on your00:00:34
computer for this Open any00:00:36
terminal on Mac I use it ram You00:00:39
can also use the default terminal00:00:42
If you are a Windows user00:00:44
You can for example use00:00:45
powershell or git bash00:00:48
here in the terminal enter python minus00:00:50
Minus vorusion If you are working on Mag00:00:53
enter Python Free minus Minus varusion00:00:56
because on macos there are two00:00:59
different versions of python available in this00:01:01
crash course We will use the00:01:02
third version of python on Windows or00:01:06
Linux Just enter Python minus Minus00:01:08
voroshin Let's check the version I see00:01:11
that python version 3.9.4 is installed on my computer00:01:13
If you see an error00:01:17
instead of version So you need to00:01:19
install python00:01:21
to install python go to the00:01:23
python.org download page and download00:01:26
python for your operating system it00:01:29
available for Windows Linux and macos00:01:32
And after that, double-check the version of00:01:35
python If you see a specific version00:01:38
in this output, then python is installed00:01:41
[music]00:01:45
let's start learning python and in the00:01:48
first part of this course we will00:01:50
use an interactive00:01:51
python shell, to enter such a shell you00:01:54
just need enter Python in the terminal00:01:56
on Windows or Linux or Python 3 on00:01:59
macos And after that press Enter the00:02:02
interactive shell was launched and00:02:04
here I see details about the specific00:02:06
version of python in my case I am using00:02:09
python 3.9.4 and here is the exact version and also00:02:14
below you see the interactive command00:02:16
line consisting of three characters more And00:02:19
now here you can enter any00:02:21
Python commands and the Python interpreter00:02:24
will interpret them and return the00:02:26
result for example Let's call the00:02:29
Print function which will print the00:02:31
result of a certain expression into the00:02:33
terminal and here in these brackets where we00:02:36
call the print function we can enter00:02:38
say a line00:02:40
and press00:02:42
Enter00:02:43
and I see Hello From Python here in this00:02:46
interactive shell you can also00:02:49
pass several expressions to the Print function00:02:51
for example the string ABC and the number 1000:02:54
and I see ABC and 10 in the terminal00:02:58
[music]00:03:02
Now let's talk about basic types00:03:05
in Python there are types like integer00:03:07
integer without decimal part float00:03:10
number with decimal part for example 2.500:03:14
string string ABC and you can00:03:18
use either double or single00:03:20
quotes boo Len00:03:22
boolean True or Falls NAN00:03:26
is used to represent an00:03:28
undefined value you can also00:03:31
check the type of any value using00:03:33
functions Type00:03:35
and Let's check the type of number 2 I see00:03:39
a class Why class because python00:03:43
is an object oriented00:03:45
programming language and any value in00:03:48
python is an instance of a00:03:50
certain class and here we see00:03:52
that number 2 is an instance of the class00:03:54
integer Let's check the type of a00:03:58
floating point number 1.5 I see fleet00:04:01
Let's check the type of the string ABC for example00:04:05
class string Let's check the type of the00:04:08
value false or True see boolean and00:04:11
Let's check the type of the value NAN see the00:04:14
class NAN Type00:04:16
[music]00:04:20
You can very easily convert a00:04:23
value of one type to another using00:04:26
functions like STR string int00:04:30
integer float floating point number and00:04:33
Boolean I can convert to a string00:04:35
for example the number 100 we get the string 10000:04:38
also I can convert a00:04:40
Boolean value to a string for example True I00:04:43
get the string True Let's convert the00:04:46
string 50 to an integer I get the00:04:51
integer 50 Let's convert the00:04:53
Boolean to an integer value True I get00:04:56
one and if I convert Falls then of course00:04:59
I get 0 Let's try00:05:01
to convert a string00:05:04
like ABC to an integer and python of course could not00:05:07
convert such a string to an integer00:05:09
and I got an error00:05:15
[music]00:05:19
in Petunia As in many others in00:05:22
programming languages there are false values00:05:24
false value is the value of different00:05:27
types which are converted to boolean00:05:30
value false and in python you can00:05:32
convert any value to00:05:34
boolean value using00:05:36
bool function there is following false value00:05:38
integer 0 during conversion we00:05:41
get false value false00:05:44
floating point number 0.0 empty string of00:05:47
course the logical value false and00:05:50
NAN00:05:51
also false are empty values of00:05:54
container types for example an empty00:05:57
list or an empty dictionary we will talk about00:06:00
container types a little later in this00:06:02
course00:06:04
[music]00:06:08
petunia You can Declare new00:06:10
variables and assign a value to them, it is00:06:13
customary to call variables lowercase00:06:15
letters underscores between00:06:18
words for example may underscore00:06:20
name Or for example may underscore00:06:23
fairate underscore dream00:06:26
If you want to create a constant00:06:28
whose value will not change00:06:31
during the life cycle of a00:06:32
python application you should use capital00:06:35
letters for example may underscore00:06:37
API and underscore ki but Please00:06:40
note that python does not differentiate between00:06:42
variables and constants and for python it makes no00:06:46
difference whether you name the variable T-shirts00:06:49
in upper case or T-shirts in lower00:06:52
case in both cases you can00:06:54
later reassign a different value to this00:06:57
variable But if you name00:06:59
the variable this way it will be an00:07:02
indicator for you that you should not00:07:04
assign a new value to such a00:07:06
variable00:07:07
[music]00:07:11
declaring a variable and assigning a00:07:14
value to it can be very simple My Name =00:07:17
Bogdan Now I can00:07:20
access the value of this variable at00:07:23
any time I get the string Bogdan00:07:25
also I can check the type of the variable My00:07:28
Name I get a class STR string Python00:07:32
is a dynamically typed language and this00:07:35
means that you can change the type of00:07:37
value that is assigned to a variable00:07:39
For example I can assign a new value00:07:41
True to the variable My Name and now if I00:07:45
read the value of the variable My Name I00:07:47
will get True and now the type of the variable is Bull00:07:51
This is why you should use a00:07:53
meaningful name for the variable To00:07:56
avoid such accidental00:07:58
reassignment of values if the name of the00:08:00
variable is My Name then of course you00:08:03
understand that you should assign a string to00:08:05
such a variable Let's change the00:08:07
value of this variable back to00:08:09
Bogdan If you want to for example00:08:11
assign a boolean value to a00:08:12
variable You should call00:08:15
accordingly, for example, a suitable00:08:17
name would be from loc-in for a00:08:20
variable that tracks00:08:22
whether the user is logged in00:08:25
[music]00:08:29
You can also copy variables00:08:32
for example name can be a copy of My Name00:08:35
and now if accesses00:08:38
adoraname I get Bogdan if I00:08:41
access minname I also see00:08:43
Bogdan if I assign a different value to the00:08:45
variable say Mike and access I00:08:51
will see the value Mike But if I00:08:54
access Miami it still contains the00:08:56
value Bogdan and that means that with00:08:59
basic types When you copy one00:09:01
variable to another and change the value of the00:09:03
other variable, the value of the original00:09:06
variable such as My Name does not00:09:08
change and This is due to the fact that when00:09:11
copying a variable containing the00:09:13
value of the base type, the00:09:15
values from one variable00:09:17
to another are actually copied and therefore when we changed00:09:21
the value of the atername variable in this00:09:23
line, the value of the My Name variable did not00:09:26
change00:09:28
[music ]00:09:31
Now let's define a new00:09:34
variable and Let's call it H its00:09:37
value will be the integer 21 and now00:09:40
let's assume that you want to00:09:42
increase the value of this variable H by00:09:44
one You can do it00:09:47
like this H assignment sign H + 1 we are00:09:51
actually using the current value of the00:09:53
variable H and increase it by one and00:09:57
then assign the new value to the same00:09:59
Edge variable after that the value of the00:10:01
Edge variable will become 22 You00:10:04
can also Perform the same operation00:10:06
using the operator plus equals and Let's00:10:09
assume that now we want to00:10:11
increase the value of the variable H2 H plus00:10:14
equals 2 no need two different00:10:16
operators You can use only00:10:18
one operator plus equals and now00:10:20
the variable H contains the value 2400:10:23
in the same way you can reduce the00:10:26
value of a variable using the operator00:10:28
minus equals H minus equals say 5 and00:10:32
now H is equal to 1900:10:34
Also you can assign NAN as the00:10:37
value of any variable A also you00:10:40
can delete a certain variable00:10:41
using the Dell operator and now00:10:44
there is no such variable00:10:46
[music]00:10:50
we have already discussed the basic types like00:10:52
string or integer and now it’s time00:10:55
to talk about container types in python00:10:57
there are such container types Like a sheet00:11:01
Table00:11:05
is an unordered sequence of00:11:08
values00:11:10
are ordered let's start with lists you00:11:14
can create a list using00:11:16
square brackets and here is an empty list You00:11:20
can assign an empty list to any00:11:22
variable for example now variable A00:11:25
contains a list and now it is empty You00:11:28
can check the length of the list using a00:11:31
function and now the length of the list is zero there00:11:34
is none in it element as an00:11:37
instance of a list has many different00:11:40
methods that you can call00:11:42
using dot notation if you type A00:11:45
and put a dot and press twice you00:11:47
will see what methods are available for00:11:49
use00:11:50
such as methods upend copies Count Clear00:11:53
and so on the opent method is used to00:11:57
add new elements to an00:11:59
existing one list Let's try Hey00:12:02
dot opent And let's add the number 200:12:04
now in the list A there is one element and00:12:08
now the length of this list is 1 Let's00:12:11
add another element to this list and00:12:13
add for example the string ABC and after00:12:16
that the list A already contains two different00:12:19
elements and accordingly the length A00:12:22
of course 2 You can access a00:12:25
specific element of a list using00:12:27
its index, with indices starting from00:12:30
zero i.e. the index of the first element is 0 And00:12:33
the index of the second element is 1 To00:12:35
access elements of a list,00:12:37
square brackets are used for example and square00:12:40
brackets 0 I get 2 This first element00:12:42
in this list It has index 0 Let's00:12:45
read the second element and now instead of 0 it00:12:47
will be 1 I get ABC But if I00:12:50
try to access a00:12:52
non-existent element for example00:12:53
Let's specify index 10 here I will get00:12:56
index error index out of range00:12:59
Let's add another element in this00:13:02
list is apend by the way you00:13:05
can always use Tempo to00:13:06
autocomplete for example the name of the method00:13:08
that you want to use and here00:13:11
Let's add the element True this is a00:13:13
boolean value now the length of the list00:13:15
will be 3 and let's say you want to00:13:17
access the last element in00:13:19
this list for this you can00:13:21
use syntax like hey00:13:23
square brackets minus 1 negative00:13:26
indices like -1 -2 allow you to00:13:29
access elements starting from the00:13:31
end of the list now there are three00:13:35
different elements in the list If you want to remove the00:13:37
last element in this list you can00:13:39
use the method00:13:41
without any arguments it00:13:44
returns the element which was00:13:46
just removed and now has only two00:13:48
elements also remove all elements from the00:13:51
list Using the Clear method and now00:13:53
the list is empty now Let's delete the00:13:57
variable00:13:58
[music]00:14:03
lists are mutable in python that is the00:14:05
reason we were able00:14:08
to change the value of variable A00:14:10
previous examples also have an00:14:12
immutable container type called00:14:15
Table Let's create a new variable00:14:17
B and to the right of the assignment sign we write in00:14:20
parentheses for example 2 and ABC press00:14:25
Enter and Let's access we see00:14:28
two Elements 2 and ABC and the type tapu If I00:14:34
now write by dot and twice I press00:14:36
Tap I will see only two available methods00:14:39
for taple which you can use00:14:41
count and index there are no methods00:14:44
like upend or pop and the difference between00:14:48
tapple and sheet is that00:14:50
tapple is immutable you cannot00:14:53
add new Apple elements For example00:14:56
even if I try to enter00:14:59
bynd and I'm leading here for example 10 I'll get00:15:02
an error the Table object doesn't have an00:15:06
apend attribute but you can access00:15:09
elements in a Table the same way we did00:15:11
with lists using00:15:13
square bracket notation Bi square00:15:15
brackets 0 and I see two This is the first element00:15:19
in the taple with index 0 Similarly I can00:15:22
access the second element with00:15:24
index 1 we see the row ABC also00:15:27
Using the Index method you can get the00:15:29
index of a particular element for example the00:15:32
index of the row abc-1 I recommend you to00:15:35
use00:15:36
Table when you need to create an00:15:38
ordered list with different values00:15:40
and you do not plan to change these values00:15:43
or adding a new value in the future00:15:46
That's what tapala is best for00:15:50
[music]00:15:54
Let's move on and on Let's00:15:56
discuss unordered container types00:15:58
dictionaries and sets and let's start with00:16:01
dictionaries dictionaries are created using a00:16:03
pair of curly braces with00:16:06
key value pairs inside them Let's00:16:08
add Q1 with the value True and kitu with the00:16:13
value let's say 10,00:16:15
I note that the order of the keys in the dictionary does not matter,00:16:19
you can enter Q1 and after00:16:22
it kitu, or change the order and00:16:25
first enter kitu with its value and00:16:28
then Q1 with the value True Okay,00:16:31
let's create a new variable and00:16:33
call its Person and assign it a dictionary00:16:36
with one key name whose value00:16:38
will be a string for example Bogdan if I00:16:42
get access now I will see a dictionary with one00:16:44
key name and the type of the variable is of course00:16:48
now a dictionary00:17:48
And now I get the string NAN you00:17:53
can also assign a default value by00:17:55
calling this function if a certain00:17:57
key is not present in the dictionary using the00:18:00
following syntax sail dot Get00:18:03
Age and here after the comma the00:18:05
default value for this key is specified00:18:07
for example 18 And now I see 18 as the00:18:11
result of calling this function So00:18:13
if you are not sure whether a00:18:15
specific key is present in the dictionary or not I I00:18:17
recommend that you use the Get method00:18:19
instead of square brackets, when00:18:21
using which you will receive a00:18:23
key error. If a certain00:18:26
key is not in the dictionary. Now let's00:18:28
check what methods other than Get are available00:18:30
for use for the Person dictionary.00:18:32
Let's write a dot and press00:18:36
type twice and here you can see methods such as Clear00:18:39
Kiss or velos but unfortunately00:18:42
dictionaries don’t have such a method as append then00:18:46
how can we add new keys00:18:48
very simply using square brackets00:18:52
we will write proston and here in square00:18:55
brackets we will indicate the line with the new key and00:18:57
say Happy and the value of this key00:18:59
will be True now I will see in the Person dictionary00:19:02
two different keys name and Happy00:19:06
Also you can always change the value of a00:19:09
certain key using the same00:19:12
notation Let's change the value of the00:19:15
Happy key for example to false and now00:19:17
the value of the Happy key is false let's00:19:21
change Natra back you can also00:19:23
get the length of the dictionary using the00:19:26
LAN function call it Land parson I see two00:19:31
now this dictionary has two different00:19:33
keys using parrotion.kz and00:19:37
parson.vlius you can get the keys and00:19:40
values of a specific dictionary Let's00:19:43
first try sail dot Kiss as00:19:46
a result I get the dictionary keys and00:19:50
here you see a structure that is very00:19:52
similar to a list with two elements name00:19:55
and Happy but this result is not a list it is an00:19:58
instance of dickkiss Let's check this00:20:02
using the Type function and here it will be Pro00:20:04
Kiss I see a class00:20:07
you can always convert dickkiss00:20:11
to a list If necessary using the00:20:13
list function Person Kiss And now I see a00:20:17
list with two elements name and Happy00:20:20
in the same way you can get the00:20:22
value of the dictionary keys00:20:25
parason.vels And now I see dictated with00:20:29
two elements Bogdan and True00:20:32
in the same way you can convert00:20:34
it into a list using a sheet and here there00:20:37
will be proso.vels And now you can see a list with00:20:40
two elements Bogdan and True I remind you00:20:43
that in lists you can get a00:20:45
specific element using an annotation with00:20:47
square brackets For example, I can00:20:50
get the first element by adding00:20:51
square brackets and there will be 0 and I00:20:55
see of course Bogdan also the value in the00:20:57
dictionary can have container types00:20:59
for example a list or a dictionary Let's00:21:02
add a new key to the sail dictionary00:21:04
using square brackets and here it00:21:06
will be Let's say hobbies and the value will be00:21:09
a list and here we use square00:21:12
brackets and here in the list I will write axlebox and00:21:15
Snowboarding now parason list a00:21:18
new key hobbies has been added Let's00:21:20
check this and now in this00:21:23
perosson dictionary there are keys name Happy and hobbies00:21:25
and now If you want, you can change00:21:28
this list or add new elements00:21:30
or delete elements or change00:21:32
elements using syntax such as00:21:35
Person square brackets hobbies and then00:21:39
we will use the pop method and delete the00:21:42
last element in this list So the00:21:45
element Snowboarding was deleted and now00:21:48
remains in the list only one element00:21:50
You can also remove a specific key from the00:21:52
dictionary using the operator that is00:21:56
wassin.dl and here you in square brackets00:21:59
will be the name of the key for example hobbies and the key00:22:03
hobbies was just deleted00:22:06
[music]00:22:10
now the parason variable is00:22:12
a dictionary And what if I want to copy00:22:15
this dictionary to another variable00:22:17
for example00:22:20
let's make it00:22:25
have the same value as sail00:22:28
now Let's try to change the00:22:31
variable to droperson and for example00:22:33
Let's change the name00:22:37
square brackets name and change the name for00:22:40
example to Bob Now the name in parason00:22:45
has been changed to Bob But if I try00:22:47
to access to Person I will see that the name00:22:50
has also been changed here to Bob and the00:22:53
reason for this is that the python dictionary00:22:55
is a reference type and now both the00:22:58
variables Sails and Nad Porosson00:23:00
actually point to the same00:23:02
place in memory, the place where00:23:05
this dictionary is located00:23:07
And when you change In other words,00:23:09
you mutate this dictionary, changes00:23:12
occur only in one place in memory00:23:14
to which the variables continue to be pointed by00:23:17
the sail and the analogues of the sleep00:23:20
That is why here we see the same00:23:23
value This is called copy by00:23:26
reference00:23:27
when copying values of the base type00:23:29
for example strings or boolean values00:23:32
are copied actual value from one00:23:34
variable to another with dictionaries00:23:37
the situation is reverse we copy only00:23:40
pointers which is very important to always remember the00:23:43
same applies from lists Let's00:23:46
create a list for us simply with numbers00:23:48
for example one and two and then copy to the00:23:53
ambrosia you variable nabrus like this00:23:57
and now let's add more one00:23:59
element in the list numbrus Using the00:24:02
opent method and Let's add a number for example 300:24:05
I see that it is given the image and numbros are00:24:09
the same and the reason here is the same as00:24:12
for dictionaries the list is also a reference00:24:16
type in python and here in this line we have00:24:19
copied only the reference and not the00:24:22
actual value is the00:24:24
same value for both variables We00:24:27
just need to sketch So this is what is00:24:30
called copying by reference and00:24:31
please always Be very00:24:33
careful When you copy the value of00:24:35
types like dictionary or list00:24:38
[music]00:24:41
Now let's look at another00:24:44
container type in python which00:24:46
is called a set set sets are created00:24:49
using curly braces like00:24:51
dictionaries but the set does not have keys with00:24:54
values like dictionaries instead the00:24:57
set consists of elements and Each00:24:59
element must not be mutable this00:25:02
means you cannot insert the00:25:05
set into other dictionaries or lists for example a00:25:08
set can contain the following elements00:25:12
10 Now let's assign such a00:25:15
value to a variable like myset and00:25:18
now let's look at the type of this00:25:20
variable and I can see that myset is00:25:23
an instance of the class Set Now let's00:25:26
see what methods are available for the00:25:28
variable myset I'll press Tap twice here00:25:31
and I'll see many methods like00:25:34
copy difference from sapset and so on in00:25:40
sets there are even more than dictionaries But how00:25:43
sets are actually different from00:25:45
dictionaries Let me show you00:25:47
Let's try adding another00:25:50
element to myset which currently00:25:52
only has three elements abc-10 and B00:25:56
Note that the order of these elements00:25:57
here in this output is different from the00:26:00
order in which I initially added00:26:02
the elements when I assigned the value to the00:26:04
myset variable the order was ABC B and 1000:26:07
but here in this output I see ABC 10b00:26:10
This means that the order in sets00:26:13
does not matter as in dictionaries Let's00:26:16
try adding new elements in00:26:18
myset there is a method for this Let's00:26:21
add a new element True read00:26:24
the value of the myset variable and now there are00:26:27
already 4 elements in the set Let's add00:26:29
another element for example the number 20 and00:26:31
now there are 5 elements in the set But if I00:26:34
try to add an element that00:26:36
is already in the set for example Let's add00:26:38
the number 10 I will see that the set has not changed And there are00:26:43
still only Five elements in it and00:26:46
this is what makes sets unique in00:26:49
Python the set contains only unique00:26:51
values and does not add duplicates and In00:26:55
some cases this characteristic of00:26:56
sets can be very, very00:26:58
useful sets do not keep duplicates00:27:01
You can of course remove certain00:27:04
elements from a set Using the and method00:27:07
Let's remove the number 20 and it was00:27:10
successfully removed from the set00:27:13
[music]00:27:16
Now let's briefly summarize00:27:19
container types in python let's start with a00:27:22
list lists are created using00:27:24
square brackets and in they can contain00:27:26
elements of different types, for example, integer00:27:29
boolean or string, this is a list, then there is00:27:34
tapple, created using a pair of00:27:36
parentheses, and here there can be the same elements00:27:38
as in the first list, one True and ABC,00:27:42
there are also dictionaries that are created00:27:45
using curly braces and dictionaries00:27:48
contain pairs of key values for example00:27:51
in a dictionary can be kiwan with the value 100:27:54
and tu with the value string ABC also there are00:27:59
sets created also using a pair of00:28:02
curly braces but sets have only a00:28:04
value for example one and ABC the difference00:28:08
between these four types is00:28:10
that the list of stages is ordered and00:28:15
any an element in the list of steps has its own00:28:18
unique index the index starts from00:28:21
zero the index of this element is 000:28:24
the index of this element is 1 and so00:28:26
on the difference between a list and steps is00:28:29
that lists can be00:28:32
changed You can change any00:28:35
value add new elements delete00:28:37
elements and so on on the other hand00:28:39
the value of taple type is immutable and you00:28:42
cannot change these values and also in00:28:45
tapple you cannot add or00:28:47
remove elements dictionaries and sets are not00:28:49
ordered in python the order of the keys00:28:51
here does not matter as well as00:28:54
the order of the elements in the set and you can00:28:57
access to any element in00:28:59
the dictionary by key, for example using the00:29:02
k1 or kitum key, and you can also add00:29:06
new keys if necessary00:29:10
using the Dell operator. You can00:29:12
delete a specific key from the dictionary. This00:29:15
means that dictionaries and sets are modifiable00:29:18
in Python. You can change the set,00:29:20
add new elements, delete elements.00:29:23
and so on the00:29:25
difference between a set and a list is that a00:29:28
list can contain the same00:29:30
value and a set can only contain a00:29:33
unique value and if you00:29:36
try to Add a new element00:29:37
for example ABC this set will not00:29:40
change anything and the set will still00:29:42
contain only two elements one and ABC00:29:45
in This is the difference between the four different00:29:48
container types Lis and00:29:53
Now let's exit the interactive00:29:56
python shell by calling the Exit function and00:29:59
we will spend the rest of the course in the00:30:01
Visual Studio Code editor and then we00:30:04
will talk about the functions of instructions and fls and00:30:07
other functions of python00:30:08
[music]00:30:12
in the rest of the course we will00:30:14
use the code editor Visual Studio00:30:17
Code because we will be creating00:30:18
multi-line code blocks in python and00:30:21
running it and therefore it is not recommended to00:30:23
continue working in the interactive00:30:25
shell and if you do not have vscout installed on your computer00:30:27
I highly00:30:29
recommend installing it because we00:30:32
will be using one of its00:30:33
extensions which will allow us to00:30:35
automatically execute the code using a00:30:37
keyboard shortcut or a code run button00:30:39
because if you don't have vscout00:30:42
please download it dot Visual00:30:45
studiocode.com Install And after that00:30:47
please open a terminal on your00:30:50
computer and Let's create a folder for00:30:53
our project I will do this on the00:30:56
desktop And I will create a folder called00:30:58
pythones00:31:01
Let's go to this newly created00:31:04
folder and Let's open it using the00:31:06
Cold command00:31:08
If in your case this command is00:31:11
not available You can open vscold00:31:14
manually and from the menu select the file Open and00:31:17
open this newly created folder but I00:31:20
will open it using the Cold command in00:31:23
the terminal So the project has been opened I00:31:26
will expand the application to full screen and00:31:28
also I will close this welcome page00:31:30
Now let's create new files00:31:33
here in this folder Python clashcores for00:31:36
this Click on this icon and Let's00:31:37
call the file main.pi Let's close this00:31:41
left panel and Let's write the Python code00:31:43
right in this file main.ua for example00:31:47
Let's write Print and in brackets there will be00:31:50
Hello From Python Let's save00:31:52
the changes and now the question arises how00:31:54
to run this Python application right00:31:57
here viscope we can do it00:31:59
manually by going to term menu and selecting00:32:02
New Terminal the new terminal was opened and00:32:05
you noticed that now you are in the00:32:07
Python clashcores folder so here00:32:09
enter Python and the file name you00:32:12
want to run main.ui you need to00:32:15
enter this command If you are using00:32:17
Windows or Linux If you are running00:32:19
on Mac please Change Python to00:32:22
Python Free Let's press Enter and python00:32:25
will execute the specified file and here is the result of00:32:27
executing this file main.ui Hello00:32:31
From pite but enter this command Every00:32:33
time we want to execute the code it is not00:32:36
very convenient so for simplicity00:32:38
Let's install one of the extensions00:32:40
vscout which is called Cold Runner and00:32:44
with the help we can execute this code00:32:47
much easier and faster00:32:49
using a key combination or this00:32:51
button Let's go to the extension and00:32:54
here in the search enter Call droner00:32:56
select Call 2 and click Install Cold00:33:01
Warner was successfully installed and if you00:33:04
Scroll a little down in the description you00:33:06
will find how to run it Let's find the00:33:09
key combination Here it is in this section00:33:11
to run the code You can00:33:14
use the key combination Control00:33:16
alt-n or use this button00:33:18
here Let's go to the main.ua file and00:33:22
first Let's press this button and00:33:24
select runcold and here I see the result of00:33:27
executing this file with I see00:33:31
sections like this but I don’t want to00:33:34
see them every time I run this00:33:36
program with00:33:38
and so I will show you how to change these00:33:41
settings so that these messages are also removed from the output00:33:44
we will clear the00:33:46
previous output Every time we00:33:48
run the genre again also00:33:51
Note this line on my00:33:53
computer the Python interpreter was used00:33:55
If you are a00:33:58
Meg user I will show you how to change concrete to00:34:01
python 3 Let's open the Cold00:34:03
preferences settings or by pressing the00:34:05
combination Control comma or commands00:34:08
comma and enter Code Wonder in the search and00:34:11
you will find coldroneer settings that00:34:13
contain the text Cold wanner in the title00:34:15
or description and Let's refine the search by00:34:18
adding Save here and you will find two00:34:21
options00:34:22
Save all files by restarting and00:34:24
save the file by restarting I will choose the00:34:27
second option And when you you will00:34:29
run any file using then it will00:34:32
first automatically save the file and00:34:35
then execute the code Now let's00:34:38
find Clear here and check the box here00:34:40
to clear previous output now write00:34:44
message here and you will see the show execution00:34:47
message Let's uncheck this box and00:34:51
if you are a Mac user00:34:53
enter also here in search exec And you00:34:57
will find Call oner executer00:35:00
and You need to open the file from these dot00:35:03
Jason and change the Python interpreter in it00:35:06
please click here Edit in00:35:09
settings.json Find the Python option and00:35:12
Change Python to Python 3 and save the00:35:16
changes in this settings file. js So00:35:20
now we are all set Let's00:35:22
try to execute the main.pi file again00:35:24
click here Run Cold And now I00:35:28
only see the text Hello From Python if I00:35:32
change the file and add an exclamation mark here for example00:35:33
and save the changes to00:35:36
the file I will run its words Run Cold I will see00:35:39
that the previous output has been cleared Also you00:35:43
can use the Control00:35:45
alt-n combination to execute the code faster00:35:47
Let's change the files again and press00:35:50
this Control alt-n key combination and you00:35:52
will see the updated result here with00:35:55
two exclamation marks Also you00:35:58
can change the position of the term now by00:36:01
default it is under the file and00:36:04
if you want to move it to the right00:36:06
You can right-click00:36:08
here and select move panel00:36:10
to the right and now the terminal is00:36:12
here to the right of the file for me this is more00:36:14
convenient So everything is already configured Cold00:36:17
Runner is installed and any time00:36:20
you want to run the code you need to press the00:36:22
key combination Control alt-m00:36:25
[music]00:36:29
we have successfully installed and configured the00:36:31
Cold wanner extension and we are ready to00:36:33
continue the next topic functions in00:36:36
python functions are created using the00:36:39
Def keyword followed by the name of the function00:36:42
for example My Name followed by a pair of00:36:45
parentheses and in them You can specify00:36:48
the parameters of the function, let's not00:36:51
add parameters for now, after that there is00:36:54
a colon and on the next line after00:36:57
the tap Please note that the tap was00:37:00
added automatically You can00:37:02
add the body of the function with instructions Let00:37:04
's write here just the00:37:07
keyword pass and then below Let's call00:37:11
this function My Name using00:37:14
parentheses and let's run this code the code was00:37:18
executed but here in the output I don't00:37:21
see anything Let's try to print the00:37:23
result of calling this function using00:37:28
My N like this now let's run the code again and00:37:32
now here I see NAN and this result00:37:35
is returned by the function My Name is the00:37:39
Pass keyword here doesn't actually00:37:41
do anything and you can use00:37:44
such a keyword in the function body00:37:46
when the function does not contain any code But you00:37:49
need to add at least one line of code00:37:51
in the function body so in that case you00:37:54
should use PAZ so that the00:37:56
function body is not empty Now when00:37:58
a function is declared we can call00:38:00
multiple times For example I can copy00:38:02
this line and call it again And now00:38:05
I see on Twice So Now this00:38:07
function My Name has a name but does not have00:38:10
any parameters and by default00:38:12
the function returns NAN if there is no00:38:15
statement Let's add the string he00:38:18
instead of pass and Let's return for example00:38:20
the number 10 like this if I run00:38:24
the application now I will see the number00:38:27
10 twice this is how you can return a00:38:30
specific value from a function00:38:31
Using the Return keyword Now00:38:34
let's add parameters to the function My00:38:37
Name the parameters of the function are added here00:38:39
in parentheses and Let's add the00:38:41
name parameter Now we can call the00:38:44
My Name function with an argument I can00:38:47
add an argument here for example Bogdan00:38:50
And in the next function call I can00:38:52
add another argument for example Bob and00:38:56
now let the function return name00:38:58
instead of the number 10 Let's00:39:01
run the application again after these changes And00:39:03
now I see Bogdan and Bob as00:39:06
the results of a function call00:39:08
Note that this is a parameter And these are the00:39:11
arguments here argument and here00:39:14
argument Every time you call00:39:16
a function you pass different arguments00:39:20
also Note that if you do not00:39:22
specify an argument for example Here you00:39:25
will get the error missing required00:39:27
positional argument and in this case you00:39:31
can assign a default value00:39:33
for a certain syntax parameter00:39:35
next after the parameter we add an00:39:38
equal sign and here there can be a default name00:39:41
for example No Name specifite like00:39:43
this let's now run the application and00:39:47
now for this function call I see00:39:49
Bogdan And in this calling the function I see00:39:51
noname spicefight because now00:39:55
this function parameter has a00:39:58
default value No Name spicefight this is the00:40:01
default value for the name parameter00:40:04
actually inside this function this00:40:07
name parameter is a variable and00:40:10
you can perform various actions with00:40:13
such a variable for example instead of00:40:14
returning name we we can return00:40:17
name.app and call this method like this,00:40:19
let's now run the application and00:40:22
now here I see Bogdan and noname00:40:24
special in uppercase because00:40:27
here on this line we called apr the00:40:30
variable name contains a string And each00:40:33
line is an instance of the class00:40:34
string A in the class string there are many00:40:37
methods available including Apple so we can00:40:40
call it using dot rotation00:40:42
like this also inside the body of the function You00:40:45
can perform some actions00:40:47
for example Here Let's display the terminal00:40:48
name valve is And after the comma we write00:40:52
name Now let's run the application00:40:55
and here I see name Welly from Bogdan What00:41:00
is the result of this expression00:41:02
then I see Bogdan What is the00:41:05
result of the function call that we00:41:07
print here on this line then I00:41:10
see name Wild is No Name specified this is the00:41:12
result of the Print function call inside the00:41:14
My Name function and at the end we see00:41:16
the noname specific in upper case that00:41:20
is returned function My Name in this00:41:22
function call This means that the00:41:25
Python function can do some00:41:27
things like we did for example in this00:41:28
line return a result like we00:41:31
did here in this line also00:41:33
Note that if you do not00:41:36
use ration inside the function body00:41:37
then any function does not explicitly return NAN00:41:40
and this is what we saw at the beginning of this00:41:43
lesson00:41:44
[music]00:41:48
now Let's delete this function and00:41:51
let's define another function again00:41:54
using the DF keyword And the name of the00:41:56
function will be Person underscore00:41:58
info and here in the parameters section00:42:01
Let's add two parameters and H followed by00:42:05
a colon and on the next line there will be00:42:08
the body of the function. Please note that if00:42:10
you try to write a function block without00:42:12
indentation, for example, let's00:42:15
run the code like this, you will see an error: indentation00:42:19
expected code block with indentation00:42:22
because Python, with the help of indentation, actually00:42:25
understands where the body of the function begins,00:42:27
so you should always add00:42:30
here indentation and if I run the code now I wo00:42:33
n’t get any errors. So let’s now00:42:36
display age and name in the terminal info00:42:42
in the next line00:42:46
below Let’s call a function00:42:48
with two arguments for example Bob and 2500:42:53
Let’s run the application and here in00:42:55
the output I see Bob and the number 25 This00:43:00
means that at the time this00:43:03
function was called, the name parameter was assigned00:43:05
the value Bob and the H parameter was given00:43:08
the value 25 and these arguments here in this00:43:12
function call are called positional00:43:15
arguments if I change the order here00:43:18
and For example, if I pass the first 25 and the00:43:21
next Bob I will receive another the result is00:43:24
25 this will be the name H will be Bob and this is of00:43:29
course not what you expect from this00:43:32
function This means that with positional00:43:35
arguments the order is important so when00:43:37
you call the sailsinfo function and00:43:40
add a couple of parentheses without Scott will00:43:44
actually show you what arguments00:43:46
are00:43:47
expected first the argument is name Here00:43:50
you can see that name is underlined if00:43:53
I type Bob and add a comma I can see that00:43:56
now I need to add H as a second00:43:58
positional argument00:44:00
[music]00:44:04
but also in python you can use00:44:07
keyword arguments like this00:44:10
name next equal sign Bob comma00:44:15
next equal sign 25 Let's now00:44:19
run this code and I can see that the function00:44:21
Was executed and here is the expected result00:44:24
namebop and h25 And now I can change00:44:29
the order of these named arguments like this,00:44:31
first H will be the value 25 and the00:44:35
next one will be name with the value Bob00:44:40
Let's now run the application and00:44:43
the result is the same this means that with00:44:46
keyword arguments where we00:44:48
explicitly specify the parameter name the order of00:44:50
the arguments does not matter if you00:44:54
want you can even mix00:44:56
positional Arguments and keyword arguments00:44:58
for example first would be00:45:00
Let's say Bob Let's remove this00:45:03
keyword argument name and00:45:05
Let's pass Bob through a positional00:45:08
argument he will be the first and the next one00:45:11
will be the keyword argument Let's00:45:13
now run the code and the result is the same00:45:15
Bob and 25 This means that you can00:45:18
mix positional Arguments and00:45:21
named arguments00:45:23
[music]00:45:27
Now let's create another function00:45:30
and call it will be allowed by Dev Sam himself and00:45:34
here there will be, say, two parameters A and B and00:45:38
I want to return the sum a/b Like this and00:45:43
Let's call this function below and00:45:46
Let's print the result of the00:45:48
function call to the terminal here it will be itself with00:45:51
two arguments 5.2 Let's now00:45:53
run the application and I get 7 output00:45:57
And if I want to sum up all the arguments00:46:00
that are passed to a function call00:46:02
for example 5 2 10 15 and so on if I00:46:07
try to run the application now I00:46:09
will get an error like itself Accepts two00:46:12
positional arguments but were passed 400:46:15
this is logical here we specified only two00:46:18
parameters but we have passed four00:46:20
arguments and it leads to this error00:46:23
in python but how can we solve this00:46:26
problem that if I want to call a function00:46:28
with any number of arguments and here00:46:31
inside the function I want to sum all the00:46:33
passed arguments for that inside the00:46:36
parameters section I can use the00:46:38
following syntax star arks and00:46:42
now let's print terminal arks00:46:45
like this let's see what we get00:46:47
in the output and I see a tapa with the values 5 200:46:51
10 and 15 this means that now we can00:46:54
call this function itself with any00:46:57
number of arguments00:46:59
using this syntax in the00:47:01
parameters section this is a variable arks will be00:47:03
defined inside the function and it will00:47:06
actually contain all the arguments00:47:08
that were used in the function call00:47:11
Let's also print the type of the variable00:47:14
arx like this, run the code and I see the00:47:18
tattoo class here00:47:19
[music]00:47:23
And now I can iterate through all the values00:47:26
in arks and sum everything values of numbers00:47:29
and Let's get started with this but00:47:32
first Let's declare a new variable00:47:34
Total its initial value will be00:47:37
zero00:47:39
Now let's iterate over the Arguments and you00:47:42
can iterate using a loop00:47:45
for ark in ark colon and here Let's00:47:49
do the following operation Total plus00:47:52
equals and at the end Let's return Total00:47:55
soon I'll explain to you what's happening here00:47:58
But now let's Just run this00:48:00
code and I can see the result 3200:48:03
So what's happening here here in00:48:07
this line we're iterating over the arguments00:48:09
each value of the container type00:48:11
is irable We just saw00:48:14
here that arx is the floor research we00:48:17
we can iterate over the elements of Table and00:48:19
Let's output it here inside the for loop,00:48:22
let's say in the terminal just And let's00:48:26
run the code I see 5 2 10 15 and at the end00:48:30
I see 32 What is the result of calling00:48:32
this function and this means that inside the00:48:35
for-in loop there is a variable with the name00:48:38
exactly in the loop this variable00:48:40
is defined and we can perform00:48:42
some actions with such a variable in00:48:45
this example it is an integer and in this00:48:48
line we simply add Edge to the00:48:50
value of the Total variable which was00:48:53
declared here before forin using the00:48:56
plus equals operator And after this00:48:58
for in loop the value of the Total variable will00:49:01
contain the sum of all arguments and00:49:04
therefore here when we return Total00:49:06
we get the sum of all arguments00:49:08
passed in this function call if I00:49:11
delete this line and add for example00:49:13
another element here Let's add 10 and00:49:16
run the application we will get 42 and it doesn’t00:49:20
matter Which number of00:49:22
arguments Here you pass in this00:49:24
function call they will all be00:49:25
summed here in this for loop00:49:29
[music]00:49:33
now let's talk about keyword arguments00:49:35
Let's remove everything from00:49:38
here and Let's declare the function00:49:40
info again here we'll add two00:49:43
parameters again and Let's print out the terminal00:49:46
name.h like this, let's call this00:49:50
info function below with two arguments Bob and00:49:54
25 as we did before and Let's00:49:57
now run the applications again and I00:50:00
will see Bob and 25 in the terminal But what if00:50:03
you want to specify a variable00:50:05
number of parameters here and not just two for00:50:07
example, and let's say that you want00:50:11
to extend this function and add other00:50:13
parameters, for example, city, country, hobby, and00:50:17
so on, well, not all calls to the function00:50:20
must have all the Arguments and you00:50:23
want to be able to call this00:50:24
function, say, with only two00:50:26
arguments, name and age, but in00:50:29
some cases you want to pass00:50:31
more arguments for example00:50:33
age age and city how to perform00:50:35
such tasks You can use KW00:50:39
arks and the following syntaxes Two00:50:42
asterisks arks Like this, let's00:50:46
display the arks terminal here and run00:50:48
the application00:50:50
and I now get in the terminal an error of00:50:53
type00:50:54
takes 0 positional arguments but00:50:58
was passed two This means that with00:51:01
this syntax in the parameters section00:51:03
you are not allowed to use00:51:06
positional arguments because in this00:51:09
function call00:51:10
you must only use00:51:12
named arguments or keyword arguments00:51:16
let's change the00:51:19
positional arguments here named00:51:21
arguments here will be name And here will be00:51:24
H like this let's now let's run the00:51:27
application And now in the output I see a00:51:30
dictionary with two keys name with the value00:51:33
Bob and H with the value 25 This means that00:51:37
when using named arguments00:51:39
and two asterisks before arks the arguments are00:51:42
converted to a dictionary Let's00:51:45
make sure something is a dictionary Let's00:51:47
output Type arax and run the application and00:51:50
Yes, we see the dictionary class here and now00:51:53
here inside this function You can00:51:55
work with the Ax variable just like you00:51:58
work with any dictionary00:52:00
You can access the keys You00:52:02
can add new keys You can00:52:04
change the value of the keys and so on For00:52:06
example, you can print arx square00:52:09
brackets name and now you will get00:52:12
the value of the key name in this dictionary and in00:52:16
this example this is Bob00:52:18
also Let's add here for example a00:52:20
city let's say Paris and now I can00:52:24
access this city like this00:52:27
let's run the code and I will see in the00:52:30
terminal Paris but what if the city00:52:33
is not passed here as a named00:52:35
argument what will I get I will get an error00:52:38
error this is a network key error and this is00:52:42
what we discussed earlier If you00:52:44
try to access a00:52:46
specific key in a dictionary00:52:47
using square brackets and00:52:49
that key is not in the dictionary you will get a00:52:51
Key error if the key may00:52:54
be present Or maybe not You should00:52:57
use the method Like this arks.g and00:53:01
here it will be for example networks if I execute00:53:04
the code Now I will see the output One because00:53:06
this is the value that is returned by the00:53:08
Get method if the abandoned key00:53:11
is not in the dictionary And now in this00:53:13
call function there is no named00:53:15
network argument and therefore in the arks dictionary00:53:18
the key is City and of course if you want you00:53:21
can assign a default value00:53:23
for this key for example new york And00:53:26
now I will get new york here on this00:53:28
line like this you can collect all the00:53:30
named arguments into a dictionary00:53:32
using two asterisks in the00:53:34
parameter block And the name of the variable, of course,00:53:37
can be different, not necessarily. For00:53:39
example, you can change arox here to00:53:42
Person and change it in other places and00:53:44
also after running the code I will see the00:53:47
same result So that's all for00:53:50
arguments with keywords in Python00:53:53
[music] it is a00:53:57
sign of good form to00:53:59
add a description to every function00:54:02
you declare in python and this is00:54:04
done as follows Let's00:54:06
declare a function called self with two00:54:08
parameters a/b and here the kilo00:54:11
function description is added to the beginning of the00:54:13
function body using 3 double00:54:16
or single quotes so Let's00:54:19
Add them and here between them we will add a00:54:22
description of this function sums two00:54:25
numbers So let's return A + B and00:54:30
now if below I call this function I00:54:34
will see the description here in this popup00:54:37
window sums two numbers And now I can00:54:40
call this function with two arguments00:54:42
let's say 2 and 5 and as a result I will get 7 and00:54:46
if you want you can output this00:54:49
result to the terminal like this, run00:54:51
the application and I see 7 in the output like this00:54:54
the description of the function is added also If00:54:57
you want you can split it into00:54:59
several lines like this so summing two00:55:01
numbers the numbers must be integers,00:55:05
we launch the application after this and I00:55:08
see the same result and now if I00:55:11
hover the mouse over myself I will see a changed00:55:14
description summing two numbers the numbers must00:55:16
be integers this is a multi-line description00:55:19
of the function So that's all about the00:55:21
Python function00:55:23
[music ]00:55:27
Let's now talk about00:55:29
comparison operators in python equal not equal more00:55:34
less more or equal and less than or00:55:38
equal and the expression with all these00:55:40
operators are converted to boolean00:55:43
value True Or false let's declare00:55:45
two variables and integer 10 and bir00:55:49
integer 12 and Let's output00:55:52
terminal comparison sign B let's execute the code and00:55:56
we will get false because this00:55:58
expression returned the boolean value00:56:00
false because Hey is not equal to b if I00:56:04
change B to 10 then I will get the boolean00:56:07
value True But what if there is a string00:56:10
let's say 10 like this let's see00:56:12
what we get we will get false00:56:15
because now these variables have different00:56:17
types, here is an integer intenger and here is00:56:21
a string and in this case such an expression with the00:56:23
comparison operator will return false00:56:25
Okay, let's go back to the number 5 for00:56:28
example and Let's duplicate this00:56:31
line several times here it will not be00:56:34
equal here it will be greater here will be00:56:38
less next will be greater than or equal to and at the00:56:42
end will be less than or equal to Let's00:56:44
run the code and I'll get the following00:56:47
results which are pretty obvious00:56:49
this is actually basic math00:56:51
if these values are the same00:56:54
Let's change the value of variable A to00:56:57
5 and run the code I got True on this00:57:00
line A is equal to B And I will also get on00:57:04
these lines Hey greater than or equal to B and00:57:07
less than or equal to B This is00:57:10
how comparison operators work and00:57:13
again an expression with such00:57:16
operators always returns a Boolean00:57:18
value either True or false00:57:21
[music]00:57:25
now let's talk about logical operators00:57:27
in python such as and or and not an00:57:32
expression with logical operators or00:57:35
return a specific value00:57:39
an expression with an operator does not return00:57:42
True Or false let's First look00:57:46
at the operator and Let's declare two00:57:49
variables with the value ABC and B00:57:52
with the value 5 and here Let's print the00:57:55
result of such an expression like Hey and00:58:01
Let's see what we get and I00:58:04
see 5 and that's actually the value of the00:58:07
second operand in this expression with the00:58:10
operator and00:58:11
if I change Hey to an empty string This is00:58:15
how I get an empty string as the result of00:58:17
this expression Why Because the00:58:21
and operator always returns the first00:58:24
value is false and the value of A is00:58:27
false it is an empty string Or for example00:58:30
if it is 0 it is also a false00:58:33
value we discussed false value00:58:35
earlier I will get 0 after running this00:58:38
code But usually operators like and or00:58:41
and are not used in conditional statements00:58:44
and we will talk about them a little later and the00:58:47
result of such an expression will be00:58:48
true if both operands this and this are00:58:52
true But if at least one of the operands00:58:56
this or this is false then the result of00:59:00
such an expression will be false Let's00:59:03
print in the terminal00:59:05
the result of the conversion to a Boolean00:59:07
value expression a and b Let's00:59:10
execute code And now I see false00:59:14
Because one of these values is false00:59:17
This is if I change Hey to the number 10 and00:59:22
run the code I will get True because00:59:25
now this expression is true both values are00:59:28
true00:59:30
If by is let's say false let's say00:59:33
NAN the result will be false because00:59:37
NAN is also a false value. If it00:59:41
is NAN and bi is, say, the number 5,00:59:44
the result will be the same because it does not00:59:47
matter which of the operands is false,00:59:50
either this one or this one, in both cases we00:59:54
will get here in this line false00:59:57
[music]01:00:01
also if I add here another01:00:04
variable for example si its value will be the01:00:06
string A and here I will add it to this01:00:09
expression and C and Let's add it01:00:13
here too and that's it and run the code I will get exactly the01:00:17
same result as before here in01:00:19
this line I will get Nan this is the value of01:00:21
the first operand and here in this01:00:24
expression And in this line I will get false01:00:28
and this means that it doesn't really01:00:30
matter what values the BBC has01:00:33
here in this expression because Python01:00:36
sees that the value is false01:00:39
so there is no need to evaluate all the01:00:41
following expressions here and here01:00:44
Because here we see actually an01:00:46
expression and python stops here01:00:48
in this example after evaluating the first01:00:51
expression because this expression is false01:00:54
But if hey nice for example in the string ABC01:00:59
then python will continue evaluating the other01:01:02
operands And now I get A is the01:01:05
value of the last variable C because01:01:08
that the value of A is true so we move on01:01:11
to the next expression the value of B is also01:01:15
true so we continue and finally01:01:18
we evaluate the last expression it is01:01:21
also true and therefore its value01:01:23
is returned as a result of the entire01:01:25
expression with two operators and the01:01:27
result is ultimately true if01:01:30
it is converted to a boolean value But01:01:33
if by is false for example 0 then C01:01:36
will not be evaluated and python will stop01:01:39
here after evaluating the expression B and this01:01:44
is called short circuit evaluation01:01:46
does not matter what happens next if01:01:49
we have already found the first false value in01:01:51
such an expression01:01:52
it is immediately returned as the01:01:55
result of the entire expression the remaining01:01:58
part is not processed For example, I can01:02:01
replace C here with a function call Print01:02:04
not Cold like this, let's execute this01:02:07
code and I don't see that the Print function is01:02:10
called because the01:02:12
evaluation did not reach this expression, this function call01:02:16
is actually an expression here But01:02:20
if we change the value of bin to true01:02:22
value for example 2 then I will see in01:02:24
the terminal not Cold because now this01:02:27
expression has been evaluated the01:02:29
function print function actually01:02:31
returns NAN So here on this01:02:33
line we get NAN as a result of01:02:35
this whole expression But in this line01:02:38
we still see True Because01:02:41
here I haven't changed C to Print esi is01:02:44
still true so this whole01:02:46
expression is true this01:02:48
is called short circuit evaluation in01:02:51
python01:02:52
[music]01:02:56
ok Let's move on And now let's talk about the01:02:59
or operator Let's remove and from here01:03:02
like this and Let's remove and also from here01:03:05
and Let's replace here and with or and01:03:10
let's get rid of the variable C like01:03:13
this let's now run the code and I01:03:16
get ABC as the result of the expression or01:03:20
B and this expression is true01:03:23
so here I get True And as you01:03:26
can see the result of the whole expression01:03:28
is the first true value01:03:32
i.e. the value of this expression if I01:03:35
change the value and for example to an empty01:03:38
string this is a false value then in the end we01:03:41
will get 2 this is the value of B but still01:03:44
this whole expression or true it will be01:03:47
false only in one case if both01:03:51
operands are false01:03:53
for example A is an empty string AB NAN Let's01:03:58
see what we get now I see for01:04:00
us this value of the last operand B in01:04:03
this expression and of course this01:04:06
value is false so here I get01:04:09
false and this proves that such an01:04:11
expression will be converted to false01:04:14
only if both operands are01:04:17
false You can of course add more01:04:20
one operator or here for example or c01:04:23
and Here we will also add or c and Let's01:04:27
declare a variable c and assign a01:04:30
number to it for example 10 Let's execute the code And01:04:33
now I get a true value01:04:35
because one of the operands is01:04:37
true it is strength and its value is01:04:40
returned as the result of the entire01:04:42
expression The rule here is the same as01:04:44
before, the result of the entire expression01:04:46
is the first true value. But01:04:49
if it is also false, for example 0, I01:04:52
will get A01:04:56
or B or SIM as a result of the entire expression, and of course such a01:04:58
value is false, so here I01:05:02
get a fold as a result of transforming01:05:03
this expression to boolean But as01:05:06
soon as python finds the first true01:05:09
value for example the string ABC Let's01:05:12
run the code it will be returned as the01:05:15
result of the entire expression and python01:05:17
stops and does not evaluate all the01:05:20
remaining expressions Now this is the01:05:22
operator or is also the01:05:25
short circuit operator01:05:26
[music]01:05:31
Now let's look at the operator not01:05:33
which returns either True Or false01:05:36
let's declare only one variable A01:05:39
and Let's assign a string to it Like this and01:05:42
Let's print the terminal not A Let's01:05:44
see what we get we see false01:05:47
Because now the value of A is true not A01:05:51
is false But if A is an empty01:05:54
string I of course will get True because01:05:57
now the value of L is false and the negation of a01:06:00
false value gives True you can01:06:04
use the operator more than twice like this01:06:06
not not in this example I get false01:06:10
because Hey now the01:06:12
value is false this expression is equivalent to01:06:15
this01:06:16
function call in both cases I get01:06:19
false If you want to check01:06:22
whether a particular value is false or not,01:06:24
it is better to use such a conversion01:06:26
to a Boolean value rather than a double01:06:28
negation01:06:29
[music]01:06:33
Of course you can combine01:06:35
various Boolean and01:06:37
comparison operators for example an01:06:39
expression such as 5 and the string ABC and not the number01:06:44
3 is valid expression in python01:06:47
Let's look at the result of such an01:06:50
expression and the result is false but01:06:52
please be careful When you01:06:54
combine operators and Or for example01:06:57
if there is an operator here or I will end01:07:00
up with 5 But if I put this part of the01:07:04
expression in parentheses and here it will be01:07:07
Here is the opening parenthesis here closing01:07:10
parenthesis I will get a different result I01:07:13
got false because now with these01:07:15
parentheses this expression must be01:07:17
true and this must be true but01:07:21
if I remove the parentheses and go back to the01:07:23
previous option This is how this01:07:25
value will be returned as the result of the01:07:27
entire expression because python01:07:30
processes operands one by one and01:07:33
here we find the first truthful01:07:35
value before the or operator and so01:07:38
it is returned as a result of01:07:40
this entire expression So if you want to01:07:43
combine or operators Use01:07:45
parentheses to influence the order in which01:07:48
python interprets expressions So that's01:07:52
all about logical operators in01:07:54
python01:07:55
[music ]01:07:59
conditional and logical operators are most01:08:02
often used in conditional01:08:04
statements and now let's talk about01:08:07
them the syntax consists of01:08:10
keywords like If lif and LS let's start01:08:14
with just the keyword If Let's01:08:17
declare a new variable and call it01:08:19
name Let's assign a value to it01:08:21
for example Bogdan and there will be conditions here If01:08:25
name Let's perform some action01:08:27
Let's print into the terminal let's execute01:08:30
the code and I see Bogdan here in the terminal01:08:33
Because now this condition is true This01:08:38
means that in a conditional If statement01:08:40
this block of code is executed only if01:08:42
the condition is true You can Add01:08:45
several here other lines of code how this01:08:47
is done in functions for example You can01:08:49
print the name twice this is a completely01:08:51
valid block of code inside a statement01:08:55
But if this condition is false For example if01:08:58
the name is an empty string then this block of01:09:01
code will not be executed01:09:04
and if you want to execute another block of01:09:06
codes in case it the condition is false You01:09:09
can use the els block like this01:09:12
and here Let's print in01:09:15
the terminal the line name is empty name is01:09:18
empty Let's run the code and I see01:09:21
one output You01:09:23
can also add a blog01:09:26
in this statement with If Let's go back01:09:30
to the Bogdan value and also Let's01:09:32
add the last name I'll indicate your last name01:09:35
here in this way and now Let's01:09:38
do the following if name then01:09:41
print name after that If we add01:09:44
another PM and blog abbreviated as lif and there01:09:49
will be one more condition01:09:51
and Let's print like this and in the01:09:56
EOS block instead of name is ampty we write name01:09:59
and01:10:02
Let's run code And now I see01:10:05
Bogdan because name is true. If there01:10:08
is an empty line or NAN here I01:10:11
should see the last name and Yes, here it is01:10:14
output if the value by comparison is also01:10:16
false for example an empty string we will see01:10:19
name and01:10:21
But what if I want to add another01:10:24
condition and output and first and last name if01:10:28
both values are not false Let's go back01:10:31
to the real values here and Let's01:10:34
think about where we should add01:10:37
another condition Let's try Add01:10:40
it here01:10:42
Let's print the first and last name into the01:10:46
terminal like this Let's01:10:49
now run the code and I see Bogdan01:10:51
because that they stop here01:10:55
if this condition is true01:10:59
python does not go to other01:11:01
lif instructions here here and here so more01:11:06
specific conditions for example this in01:11:09
our example we should place above01:11:11
before the less specific conditions like01:11:14
this and this Let's cut this from here and01:11:18
paste it here into the beginning of this conditional01:11:21
statement If and of course you need01:11:23
to change Live to If here and them to L01:11:28
And here Let's now run this01:11:31
code And now I get the first and last name but01:11:36
if the name is false This is how I get01:11:39
only the last name here this is01:11:42
how conditionals work instructions in01:11:44
Python, only one block of code is executed,01:11:47
either this or this or this or the01:11:50
last If all the previous Conditions01:11:53
were false, like for example now01:11:56
And in fact, inside Python01:11:59
converts each expression into a01:12:01
logical value This means that01:12:04
such a condition and conditions Bull calling the01:12:07
function name and equals True are identical But01:12:12
you don't have to do this01:12:14
conversion yourself, python01:12:16
does it for you so you01:12:19
only need to specify the specific expression in the01:12:21
condition and don't worry about01:12:23
converting it to a boolean01:12:25
So that's it for instructions in01:12:28
python01:12:30
[music]01:12:33
now let's talk about formatting strings01:12:36
in Python string formatting is required01:12:38
When, for example, you want to create a string01:12:41
and insert into it the value of some01:12:43
variables or integer expressions, let's say01:12:46
that there is a variable name value Bogdan01:12:49
and also from a variable say drink and its01:12:51
value T and I want to create a new string01:12:54
Bogdan likes to drink tea and I can01:12:58
do this as follows print01:13:00
Print then call the function name operator01:13:03
plus a string in it Space then like01:13:08
another space again operator plus like this01:13:12
let's execute this code and I see01:13:14
the line Bogdan like01:13:16
but this approach is inconvenient to01:13:19
use in Python there is a01:13:21
string interpolation function and you can instead of01:13:25
this entire expression, write the following F,01:13:28
then there are double quotes or01:13:31
single quotes, here there will be a name in01:13:34
curly braces, then we just continue to01:13:37
write the line like to drink That's it, and01:13:41
here there will be another expression in curly01:13:44
braces drink Let's now run01:13:46
the code and I get exactly the same the result is01:13:49
called string interpolation and01:13:52
Python interprets such an expression01:13:55
during program execution when it01:13:57
can determine the value of these01:13:59
expressions because here you can01:14:01
use any expression for example01:14:04
name uper function call and we see the name01:14:07
Bogdan in upper case between these01:14:10
curly braces You can put01:14:12
any expression, even a function call If01:14:15
you want, this function has become available in01:14:17
Python since version 3.601:14:21
and there are other available ways to01:14:23
format strings, but this is the01:14:25
simplest. In my opinion, and therefore I01:14:29
will not show you older and,01:14:31
frankly speaking, more complex approaches to01:14:34
formatting strings like this way you01:14:36
can format strings very easily01:14:38
in python01:14:39
[music]01:14:43
Let's now talk about errors in01:14:46
python programs and for example Let's01:14:48
write 10 and divide it by 0 Let's01:14:51
execute this code and I see a01:14:53
divide by zero error and if you try to01:14:56
do some other things01:14:59
after this lines of code for example Let's01:15:02
say we display the terminal Continuous01:15:05
Let's run this code then we won't01:15:08
see continue here in the output Because01:15:11
in fact the program was interrupted on01:15:14
this line where we were performing division01:15:17
by zero an error occurred and here are the details of01:15:20
such an error Therefore if you want to01:15:23
go to this example to this line and01:15:25
call the Print function you need to wrap01:15:27
this line of code in a Type except block01:15:31
using the following syntax here01:15:34
Select from the dropdown menu this option and01:15:37
After selecting you will see that viscode will01:15:40
automatically add the Strike code template01:15:43
and here Let's move this line into a01:15:46
block like this Which earlier Let's01:15:49
divide 10 by 0 And here in the Set sections01:15:52
Let's just leave the groove I remind you that01:15:56
pass is a special instruction01:15:57
that does nothing is used01:16:00
where Python expects a block of code from you01:16:04
Let's run this code now and I01:16:06
will see continue here in the output, this means01:16:10
that this is an error which occurred here on01:16:12
this line did not go beyond the scope of this01:16:15
block and, if necessary, you can01:16:17
process this error in a certain way01:16:20
that occurred here in this01:16:22
block Troy Let's look again at the01:16:25
type of error, move this line back,01:16:27
execute the code and the error was division by 0,01:16:31
make a move era We can take this01:16:34
type of error from here and put it in the01:16:36
except except Zero division block01:16:40
and here there will be a variable and Let's01:16:43
display the terminal And like this and Let's01:16:47
of course get rid of the line pass it is01:16:49
no longer needed Let's execute the code I01:16:52
see just a line01:16:53
this is the value of the variable and here inside01:16:56
the except block and this is what we get01:16:59
when we use a specific type of01:17:01
error Zero Division01:17:04
and the execution of the code continued So01:17:06
here on this line I see continue in the01:17:09
terminal like this you can handle01:17:11
different types of exceptions using Try01:17:14
except Block in python01:17:17
[music]01:17:22
latest topic in this course these are01:17:25
python modules and with the help of modules in python you01:17:27
can divide your application into01:17:30
different files and create different parts of01:17:32
your code in different files and essentially01:17:36
every file in your project that01:17:38
has a dot UI extension is a01:17:41
python module and now the application has01:17:44
only one module called main.ua01:17:46
there are system modules that you can01:17:49
use in your modules for example01:17:52
there is a module called there01:17:53
are also external modules that you01:17:56
can install if you need to01:17:58
use them let's start with01:18:00
using built-in modules in01:18:02
python and if you want to import01:18:04
some variables from another module01:18:06
you need to use the01:18:08
import keyword You can import only01:18:11
specific variables from another01:18:12
module or you can import the01:18:14
entire module for example Let's We01:18:17
lock the entire module with the name it is01:18:19
built in python and Here you can01:18:21
read that this mess module01:18:23
provides access to different01:18:25
mathematical functions Let's01:18:27
import the entire module and now here in the01:18:30
main.ua file we can access any01:18:33
variables defined in this01:18:35
mathematical module. If you write and01:18:39
put a dot, then after the dot you01:18:41
will see all the possible variables that are01:18:43
present in this module and you can01:18:46
use any of these variables01:18:48
inside the main.ua file in your actual01:18:51
module For example, you have access to a01:18:54
variable called pi this is01:18:56
actually the constant pi If you print it01:18:59
into the terminal you will see the number pi here01:19:02
it is in the same way you can01:19:05
access any variables01:19:08
you define in the math module Let's now01:19:10
create our own module Let's01:19:13
remove this from here and Let's create a01:19:16
new file in our project and call it01:19:18
on Mad Mobil the name here can be anything01:19:22
Whatever you want and add the01:19:25
dot UI extension in this our own module01:19:28
Let's define a function with the name itself with01:19:31
two parameters A and B and here Let's01:19:35
add a description for this function01:19:37
for example the Numbers chair itself in a similar01:19:41
way as we did earlier Let's01:19:42
return the plus B That's it, that's all you01:19:47
need to do here in this file And01:19:50
now we can very easily01:19:51
import this function itself from its01:19:54
own module into the main.ua module01:19:57
using the same import keyword.01:20:01
Note that the weight code suggests01:20:03
to me the name of this module because now01:20:06
it knows about the presence of such a module in our01:20:10
python application because Let's click01:20:13
Temp to automatically complete the name of01:20:15
this module and now here I can01:20:17
access any variables01:20:19
defined in this module Let's01:20:22
call the function itself declared in this01:20:24
module it Maps modial point itself here you01:20:28
see this option in the list and Let's01:20:30
call this function with two arguments01:20:33
also Here you see the names of the two01:20:36
parameters01:20:37
and description of the function itself that's the summary So01:20:40
5,6 and also Let's output the result to the01:20:43
terminal like this let's run the code I01:20:46
see 1101:20:48
here's how it's very easy using the01:20:50
import keyword You can use01:20:52
the functionality created in other01:20:55
Python modules If you want you can also01:20:58
import only specific01:21:00
variables using the following syntax01:21:02
From on Med Model import itself and now on01:21:07
this line we don't need to call it01:21:10
matmobil but just need to call the function01:21:13
itself Let's execute the code and the result01:21:15
will be the same this means that if you01:21:18
want to selectively import01:21:19
only some variables from module You01:21:22
can use this syntax From01:21:24
module name import and then come the names of the01:21:28
variables that you want to01:21:30
import If you want to01:21:32
import the entire module You can01:21:34
simply use the01:21:35
import keyword That's all about modules in01:21:38
python and that's the end of this course on python01:21:40
As you have seen python relatively01:21:43
simple language and it is very close to the01:21:45
human language There are words like01:21:48
about notes and there are not a lot of01:21:50
special characters Now you know the01:21:53
basics of the Python language And I wish you good luck01:21:55
in further learning Python Don't forget to01:21:58
like this video write01:22:00
a comment and also share this01:22:02
social media videos see you in the01:22:04
next videosDescription:
🔵 Полный курс Python [43 ЧАСА] https://www.udemy.com/course/python-ru/?couponCode=PYTHONRUAPR2024 🟠 Полный курс Python (English) [50 ЧАСОВ] https://www.udemy.com/course/python-complete-guide/?couponCode=PYTHONENAPR2024 🔥 Полный курс JavaScript [24 ЧАСА] https://www.udemy.com/course/javascript-ru/?couponCode=JSRUAPR2024 🍺 🍺 Донаты и благодарности https://buymeacoffee.com/bstashchuk ⭐️ Все мои курсы https://stashchuk.com/ 🎦 Подпишись на канал YouTube https://www.youtube.com/CodingTutorials?sub_confirmation=1 🙍 LinkedIn https://www.linkedin.com/in/bogdanstashchuk/ 📪 Twitter https://twitter.com/BogdanStashchuk 🔥 Профиль Udemy https://www.udemy.com/user/bogdanstashchuk/ Написать мне 📧 [email protected] 00:00:00 Обзор ускоренного курса Python 00:01:41 Привет от Питона 00:02:58 Базовые типы 00:04:17 Преобразование между типами 00:05:15 Ложные значения 00:06:04 Выбор названий для переменных и констант 00:07:08 Переменные и динамическая типизация 00:08:26 Базовые типы копируются по значению 00:09:28 Увеличение и уменьшение переменных 00:10:46 Списки 00:13:59 Tuples 00:15:50 Словари 00:22:07 Копирование по ссылке 00:24:38 Наборы 00:27:13 Итоги по типам контейнеров 00:30:09 Установка и настройка Code Runner в VS Code 00:36:26 Функции 00:41:45 Позиционные аргументы 00:44:00 Именованные аргументы 00:45:23 Сбор всех аргументов в tuple 00:47:20 Перебор значений с использованием цикла for...in 00:49:29 Использование kwargs в функциях 00:53:54 Описание функций 00:55:24 Операторы сравнения 00:57:22 Логический оператор and 00:59:58 Оценка короткого замыкания 01:02:53 Логический оператор or 01:05:27 Логический оператор not 01:06:30 Комбинация операторов и приоритет 01:07:56 Условные инструкции if 01:12:30 Форматирование строк 01:14:40 Обработка ошибок с использованием try…except 01:17:18 Модули Python
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