1
00:00:03,280 --> 00:00:07,540
Hello welcome to this tutorial on what Jilin y moment

2
00:00:10,130 --> 00:00:21,180
before discussing about what an environment I would like to cover some basic topics so when you install

3
00:00:21,180 --> 00:00:30,840
Python we install the python executable files a number of standard libraries and third party packages

4
00:00:31,290 --> 00:00:42,910
in our system so a directory is created in the system with a number of sub directories and finds and

5
00:00:42,970 --> 00:00:50,110
we will talk about some of the important directories of folders that are created in the system.

6
00:00:50,200 --> 00:00:56,810
The bin directory the bin directory is intended for executable.

7
00:00:57,280 --> 00:01:08,780
So mind it is the python binary file and applications will be here next is these include directly this

8
00:01:08,780 --> 00:01:14,230
contains the C header files that compile Python packages.

9
00:01:15,220 --> 00:01:17,940
The library directory.

10
00:01:18,190 --> 00:01:27,970
This directory contains these standard libraries along with the site packages folder in the site Packages

11
00:01:27,970 --> 00:01:30,980
Folder packages get installed.

12
00:01:31,090 --> 00:01:39,430
So when we use the D package manager pip in order to install packages from pi pi.

13
00:01:39,430 --> 00:01:43,810
This is where the packages get installed.

14
00:01:44,120 --> 00:01:46,600
This site packages directory.

15
00:01:46,690 --> 00:01:49,390
Now let's consider an example.

16
00:01:49,390 --> 00:01:51,600
We are developing an application.

17
00:01:52,240 --> 00:01:59,380
Application 1 and this application requires all third party packages.

18
00:01:59,380 --> 00:02:10,480
So we have installed package B one with version 1.0 or package b 2 with version 2.0 or and then package

19
00:02:10,510 --> 00:02:15,160
B 5 with version 1.0 or no.

20
00:02:15,380 --> 00:02:27,370
We have also started developing that application simultaneously application 2 and the application to

21
00:02:27,520 --> 00:02:32,480
need the packages be three before B five.

22
00:02:32,800 --> 00:02:44,790
So as you can see application one has a dependency on the package B five with was one dot or an application

23
00:02:44,800 --> 00:02:57,930
two requires the same package be filed with the next or the latest was in Washington to dot o now in

24
00:02:57,930 --> 00:03:04,060
order to develop this application application tool you need the latest version of the package B five.

25
00:03:04,440 --> 00:03:13,250
So when you go ahead and install package 5 with this was in the latest version it will all be denied

26
00:03:13,260 --> 00:03:14,670
the older version.

27
00:03:15,450 --> 00:03:25,770
An application one has a dependency on the older wash wash in one dot all of B5 and because the package

28
00:03:26,030 --> 00:03:34,380
B 5 has been upgraded in the system application one might not work as expected.

29
00:03:35,990 --> 00:03:43,970
So how do we resolve this issue such that the development of application 1 does not affect the development

30
00:03:43,970 --> 00:03:45,510
of application 2.

31
00:03:45,700 --> 00:03:55,300
And this problem can be solved using watch environment what you learn by means isolate one applications

32
00:03:55,310 --> 00:04:05,390
environment from another and what does a virtual environment watch environment allows packages to be

33
00:04:05,390 --> 00:04:13,390
installed in an isolated location for a particular application rather than being installed globally

34
00:04:13,880 --> 00:04:21,770
or watching the environment is a self-contained directory tree that contains a python installation for

35
00:04:21,770 --> 00:04:31,400
a particular version of Python plus a number of additional packages and this is a global Python installation

36
00:04:32,150 --> 00:04:40,410
which contains the different directories such as the bin include and library directories.

37
00:04:40,670 --> 00:04:48,660
And in order to avoid affecting the global Python installation here we have created what tool environment

38
00:04:49,040 --> 00:04:59,360
we e one and each watch environment has its own Python binary and can have its own independent set of

39
00:04:59,480 --> 00:05:05,020
installed Python packages in it site packages directly.

40
00:05:05,060 --> 00:05:14,890
So when we install packages from pi by using Pip all of these packages get installed in the watchful

41
00:05:14,900 --> 00:05:15,920
environment.

42
00:05:16,040 --> 00:05:27,080
When this environment is activated though the packages be one that was in one dot or b Two was gone

43
00:05:27,150 --> 00:05:28,520
to dot or.

44
00:05:29,320 --> 00:05:36,490
And then PFI which was in one dot all can be installed in this virtual environment.

45
00:05:37,540 --> 00:05:46,540
And we can create as many virtual environment as required so for application to we are going to create

46
00:05:46,630 --> 00:05:48,340
another virtual environment.

47
00:05:50,040 --> 00:05:52,170
And we do.

48
00:05:52,770 --> 00:06:03,330
And in this world environment we are going to install the packages P3 with version 1.0 or P4 version

49
00:06:03,370 --> 00:06:11,520
2.0 or p 5 version to dot or in this virtual environment.

50
00:06:11,520 --> 00:06:12,560
We do.

51
00:06:12,810 --> 00:06:23,220
So we have created two isolated independent environments so that the applications can be developed without

52
00:06:23,280 --> 00:06:25,110
affecting each other.

53
00:06:25,110 --> 00:06:33,930
The recommended way to create a virtual environment is to use the WI and we module if you're using Python

54
00:06:33,930 --> 00:06:41,250
3 and above then you should already have the BMV module from the standard library installed.

55
00:06:42,810 --> 00:06:48,920
And this is the command to create a what will and why.

56
00:06:49,560 --> 00:06:53,790
So let's go ahead and create a what an environment in the system

57
00:06:57,070 --> 00:07:06,670
in your windows is to go to the command prompt and type the command Python hyphen M V E in the is the

58
00:07:06,670 --> 00:07:18,440
module and the part where you want to create your word you'll environment then hit enter this step will

59
00:07:18,440 --> 00:07:24,750
install Python Pip and basic libraries within the project folder.

60
00:07:24,770 --> 00:07:33,340
In our example in our case the tutorial folder so let's go to this folder.

61
00:07:33,350 --> 00:07:40,610
This is the virtual environment that has been created the target directory and it has created three

62
00:07:41,120 --> 00:07:50,660
sub directories these grip directly on the bin directory contains a copy of the Python binary so let's

63
00:07:50,660 --> 00:08:02,590
go to this directory and in the been directory you have the executable files for Pip and python.

64
00:08:02,610 --> 00:08:09,470
Now let's go back let's go to the library directory

65
00:08:12,400 --> 00:08:17,520
so the library directory contains the site packages folder.

66
00:08:17,600 --> 00:08:25,720
These site packages for low contains the packages Pip and set up tools and Pip is used to install packages

67
00:08:25,810 --> 00:08:28,510
into this site packages folder.

68
00:08:31,450 --> 00:08:36,200
And then let's go back.

69
00:08:36,320 --> 00:08:39,590
These include folded is empty.

70
00:08:40,970 --> 00:08:51,530
Apart from these three folders we also have another file deep by the end B dot c g and this is a configuration

71
00:08:51,530 --> 00:08:58,250
file and the existence of this file indicates Python that there is a virtual environment.

72
00:08:58,880 --> 00:09:02,560
So we have created a virtual environment next.

73
00:09:02,750 --> 00:09:09,850
Let's see how to activate the virtual environment and then install packages into the virtual environment.