WEBVTT 00:04.760 --> 00:07.960 Before we start coding, we need to discuss virtual environments. 00:08.360 --> 00:12.520 Let's first answer the question why do we need to have a virtual environment? 00:13.080 --> 00:17.600 Let's consider you started to develop an application on your laptop using Python 3.4. 00:18.240 --> 00:23.440 This will have its respective libraries, and these libraries will in turn have their specific versions. 00:24.440 --> 00:30.760 Now consider you want to create a new application and you require Python 3.10 due to the upgrades done 00:30.960 --> 00:36.480 since 3.4 to 3.10, and you therefore like to use the newer features. 00:36.960 --> 00:42.280 Without virtual environments, you can only have one version of Python installed at a time, which means 00:42.280 --> 00:49.000 that if you come to upgrade to from 3.4 to 3.10, you run the risk of breaking some features of the 00:49.000 --> 00:51.640 first step when you continue to develop on it. 00:52.000 --> 00:57.680 This is especially the case if Python 3.10 is not backwards compatible with version 3.4. 00:57.840 --> 01:04.000 To avoid this issue, we can isolate these two apps into two separate environments, and like this. 01:04.240 --> 01:09.510 We will not have any issues to create a virtual environment or them in short. 01:09.750 --> 01:14.470 First, make sure you have your folder path set up where you will store all the code locally. 01:15.790 --> 01:20.910 This step we have already done in the last lecture, and I showed you that in my case, I will build 01:20.910 --> 01:22.750 this project under this path. 01:23.030 --> 01:24.430 Now to create the Venv. 01:24.470 --> 01:25.910 This will differ slightly. 01:26.070 --> 01:32.910 If you are on windows, Mac or Linux, make sure you are in a project directory, which in my case is 01:32.910 --> 01:34.190 YouTube LTE. 01:36.070 --> 01:40.790 There are instructions on how to create a Venv depending on your OS and the Python documentation, which 01:40.790 --> 01:44.310 I will put in the appendix of this section on windows. 01:44.350 --> 01:45.670 The steps are as follows. 01:46.510 --> 01:53.910 Type in Python dash m venv and you will also specify the name of the Venv. 01:54.150 --> 01:56.750 We can give it the same name as bank. 01:57.590 --> 02:02.830 Once it finishes initializing, you will see a folder being created with the name which we gave it. 02:05.230 --> 02:06.990 To actually activate the Venv. 02:07.030 --> 02:15.070 In my case, since I'm using PowerShell, we would write the following command to write Venv scripts. 02:15.070 --> 02:15.180 Rips. 02:17.220 --> 02:19.380 Activates the PS1. 02:19.660 --> 02:25.340 This part is referring to the PowerShell script that we have here. 02:27.340 --> 02:30.940 As you can see, the Venv environment has been activated. 02:32.180 --> 02:35.380 Now these commands differ slightly if you are using Mac or Linux. 02:35.740 --> 02:41.900 I believe that if you are using Mac or Linux, you'd have to write python3 here instead of just Python. 02:42.740 --> 02:52.500 And also in order to activate you would run a command similar to source Venv been activated. 02:56.180 --> 03:00.060 Now from here you will be able to install the libraries you need using Pip. 03:00.380 --> 03:04.420 If you want to exit your virtual environment just right, deactivate. 03:06.900 --> 03:11.420 And obviously again if you want to reactivate you would run the same command as before. 03:12.180 --> 03:16.860 You might also want to do this if you close VSCode and don't see them showing up in the terminal. 03:16.900 --> 03:17.580 No worries. 03:17.580 --> 03:20.620 If this happens, just rerun deactivate Venv command. 03:21.580 --> 03:26.610 Before we close off this lecture, I'd like to go over two concepts which I think will be useful for 03:26.610 --> 03:27.170 you to know. 03:27.170 --> 03:33.050 You might have noticed on the left hand side that I now have one K plus files showing up on the source 03:33.050 --> 03:33.890 control view. 03:33.930 --> 03:37.130 This happened because well for starters when you create event. 03:37.170 --> 03:40.650 Many files will be created in order to set up the virtual environment. 03:40.650 --> 03:46.690 But we are seeing these files here because once I initialize the git repository using the git init command, 03:46.730 --> 03:50.450 all of the files that are present locally are waiting to be committed to GitHub. 03:50.450 --> 03:51.410 So we have to press on. 03:51.410 --> 03:57.210 Here you would see all these files that are waiting to be uploaded to GitHub. 03:57.610 --> 04:03.370 However, the folder is not something you would need to commit to GitHub so we can use what is called 04:03.410 --> 04:03.690 a. 04:03.690 --> 04:04.730 Gitignore file. 04:05.090 --> 04:06.250 Let's create it right now. 04:09.290 --> 04:12.290 This creates a folder until you create a file. 04:12.290 --> 04:13.570 So go in here. 04:15.690 --> 04:17.410 Dot get ignore. 04:19.050 --> 04:23.090 And inside the git ignore file you can write venv. 04:23.890 --> 04:24.650 And like this. 04:24.690 --> 04:30.520 It will ignore any venv folders when you come to commit and push to GitHub. 04:30.560 --> 04:35.880 As you can see, once we saved, the folder here becomes transparent. 04:37.040 --> 04:39.680 Another concept we should discuss relates to Picache. 04:40.240 --> 04:46.880 When we will start to code, we'll see the spike folders being automatically created by Python with 04:47.040 --> 04:48.720 spike extension files. 04:49.200 --> 04:55.040 What is happening here is that when you run a Python script, Python compiles your code into bytecode, 04:55.080 --> 04:58.400 which is a more efficient, machine readable version of your code. 04:58.400 --> 05:01.400 And ultimately these files help your programs run faster. 05:01.480 --> 05:05.800 Same as for the folder, we can add these picache folders to the gitignore file. 05:06.160 --> 05:07.240 Let's do that right now. 05:09.920 --> 05:10.880 And we save. 05:11.120 --> 05:16.000 Now that we have also covered visual environments, we just have one more topic to cover before we start 05:16.000 --> 05:16.560 coding. 05:17.080 --> 05:22.640 It is important that before you write any piece of code, you identify what are the aims and end goals 05:22.640 --> 05:23.360 of the code. 05:23.840 --> 05:30.200 So in the next lecture, we will do an analysis of what variables will be extracted from the API that 05:30.200 --> 05:32.560 will ultimately be stored in our data warehouse. 05:33.000 --> 05:33.920 I will see you then.