1 00:00:05,550 --> 00:00:06,630 Welcome back everyone. 2 00:00:06,680 --> 00:00:09,470 In this lecture we're going to be discussing virtual environments. 3 00:00:09,480 --> 00:00:10,880 The reason we actually need them. 4 00:00:10,920 --> 00:00:17,120 And then how we can use Anaconda's built in a virtual environment manager to quickly create one. 5 00:00:17,130 --> 00:00:20,280 So Let's first discuss the motivation behind the virtual environment. 6 00:00:20,310 --> 00:00:25,020 Imagine that you've launched your web application and you're using some sort of external Python library 7 00:00:25,350 --> 00:00:30,170 that's known as a dependency because your dependence on that external Python library. 8 00:00:30,180 --> 00:00:34,800 Now the feature that library most likely is going to get updated to a newer version and often these 9 00:00:34,830 --> 00:00:38,070 updates they have new features that you want to use in your web site. 10 00:00:38,190 --> 00:00:43,860 But they also have what's known as breaking changes where their syntax has changed slightly and your 11 00:00:43,860 --> 00:00:45,870 old code won't work anymore. 12 00:00:45,900 --> 00:00:50,490 So now you have a problem where you want to use the new features but in order to use those new features 13 00:00:50,520 --> 00:00:52,620 you're going to have to edit all your code. 14 00:00:52,620 --> 00:00:54,390 So what can I do in that aspect. 15 00:00:55,150 --> 00:00:59,330 Well what you do is you use a virtual environment to help manage these dependencies. 16 00:00:59,380 --> 00:01:04,090 And that way each version of your project can have its own distinct environment or each of your projects 17 00:01:04,090 --> 00:01:05,830 can have their own distinct environment. 18 00:01:06,040 --> 00:01:11,500 Depends on how you want to organize your workflow but the basic idea here is that we can have one environment 19 00:01:11,590 --> 00:01:16,780 with certain versions of these dependencies and then create a new environment with the newer updated 20 00:01:16,780 --> 00:01:21,930 versions of those dependencies and kind of mix and match to whichever environments we want. 21 00:01:21,940 --> 00:01:24,690 And that way we don't need to worry about breaking changes. 22 00:01:24,690 --> 00:01:29,410 We can just switch out the virtual environments that we're working with now Anaconda. 23 00:01:29,410 --> 00:01:33,970 It comes with a built in environment manager and we need to run some steps at our command line in order 24 00:01:33,970 --> 00:01:37,780 to create the environment to create an environment. 25 00:01:37,930 --> 00:01:43,210 Once you've installed Anaconda at your command line all you need to do is type Konda create dash dash 26 00:01:43,210 --> 00:01:46,080 name my EMV or whatever you want to call your environment. 27 00:01:46,300 --> 00:01:47,920 And then we'll ask you yes or no. 28 00:01:47,970 --> 00:01:49,600 You can go ahead and press y to continue. 29 00:01:49,600 --> 00:01:52,120 So let me quickly explain what's happening here. 30 00:01:52,860 --> 00:01:57,150 First off we have that Khanda that's basically a keyword telling you that you're going to be calling 31 00:01:57,150 --> 00:02:02,250 Konda from Anaconda which allows you to create and do things in virtual environments. 32 00:02:02,250 --> 00:02:05,300 And once you click on the second word They're just saying create. 33 00:02:05,310 --> 00:02:10,440 So create a new environment then you have this what's known as a flag name and that's basically saying 34 00:02:10,530 --> 00:02:16,220 the next thing that's going to come right after this name flag is the actual name of the environment. 35 00:02:16,230 --> 00:02:19,520 So here the name of the environment that we're choosing is my ESV. 36 00:02:19,770 --> 00:02:21,840 So you can edit this last box here. 37 00:02:21,840 --> 00:02:22,660 My EMV. 38 00:02:22,680 --> 00:02:26,790 To call your environment whatever you want you can call it my flask environment my first environment 39 00:02:27,600 --> 00:02:28,890 whatever you prefer. 40 00:02:30,250 --> 00:02:34,320 Now it's creating an environment with a specific package already included in that environment. 41 00:02:34,330 --> 00:02:36,440 We can do is say can create dash. 42 00:02:36,460 --> 00:02:41,440 And so it's a little shorter of a flag than dash dash name and then passing the name of your environment 43 00:02:41,620 --> 00:02:48,160 space and then passen the actual specific package you want included such as numb pie or whatever package 44 00:02:48,160 --> 00:02:52,870 you're interested in to create an environment with a specific version of Python where you can do is 45 00:02:52,870 --> 00:02:57,940 say Konda create an either or dash and or dash dash name and then the name of your environment. 46 00:02:57,940 --> 00:03:03,550 Space Python is equal to and then the version of Python you want and then kind of combine these ideas 47 00:03:03,550 --> 00:03:04,020 together. 48 00:03:04,060 --> 00:03:09,430 You can create an environment with a specific package version included you say Conda create and or dash 49 00:03:09,430 --> 00:03:11,910 dash name then the name of your environment. 50 00:03:11,940 --> 00:03:16,390 The name of your package equal to and then what version of that package you want and if you ever need 51 00:03:16,390 --> 00:03:21,660 a list of all your environments you can say the envy list OK. 52 00:03:21,830 --> 00:03:24,310 So let's quickly create our flask environment. 53 00:03:24,320 --> 00:03:30,170 I also want to point out that in the resources for this lecture there's a link to the environment documentation. 54 00:03:30,170 --> 00:03:33,190 The documentation is actually fantastic for this particular topic. 55 00:03:33,200 --> 00:03:37,070 We're also going to be showing you that in just a little bit but it has basically everything you would 56 00:03:37,070 --> 00:03:40,830 ever want to know about Conon vitamins how to manage the environments how to create environments list 57 00:03:40,830 --> 00:03:45,680 environments restore environments save environments that where you can create an environment and send 58 00:03:45,680 --> 00:03:47,530 that to your coworkers or colleagues. 59 00:03:47,570 --> 00:03:51,140 But we're going to show you that quickly walk through the documentation there and then we'll create 60 00:03:51,220 --> 00:03:54,170 our flask environment that we'll be using through this course. 61 00:03:54,170 --> 00:03:56,260 Let's get started. 62 00:03:56,260 --> 00:04:01,930 All right so very quickly I just wanted to show you the documentation page in condos actually also an 63 00:04:01,930 --> 00:04:05,830 open source package man image management system and environment management system. 64 00:04:05,950 --> 00:04:10,120 And it runs on Windows Mac Office or Linux and we're mainly going to be using the environment managed 65 00:04:10,120 --> 00:04:12,430 system that Konda provides for us. 66 00:04:12,430 --> 00:04:16,750 And if you want more information about the various tasks that you can do of Khanda when you're working 67 00:04:16,750 --> 00:04:22,000 a virtual environments click on user guide and then come down here where it says tasks. 68 00:04:22,000 --> 00:04:26,770 There's also a nice tutorial section but the task is probably what you can me referring to the most. 69 00:04:26,980 --> 00:04:30,160 If you want to manage your environments then click on managing environments. 70 00:04:30,280 --> 00:04:32,340 And here's basically all the things you would ever want to do. 71 00:04:32,350 --> 00:04:37,170 Create an environment of certain commands create an environment from a thought why M-L file which is 72 00:04:37,170 --> 00:04:40,450 a way you can send environments to other people. 73 00:04:40,450 --> 00:04:44,740 You can clone environments activate de-activate and we're going to be going through that in just a little 74 00:04:44,740 --> 00:04:49,750 bit but you can also view a list of your environments use Pipp and so on. 75 00:04:49,750 --> 00:04:53,810 So lots of things you can do here remove environments share environments and that will just be on there 76 00:04:53,830 --> 00:05:01,630 if we go back here just so I can show you go to under the user guide tasks and then managing environments 77 00:05:01,630 --> 00:05:02,280 right here. 78 00:05:02,390 --> 00:05:04,800 And that has a list of everything you can do. 79 00:05:04,810 --> 00:05:09,340 So let's now jump over to our Adam text editor and quickly create environment and you can actually do 80 00:05:09,340 --> 00:05:11,010 this at your terminal command line. 81 00:05:11,200 --> 00:05:13,750 I'll do it within the Adam text editor. 82 00:05:13,750 --> 00:05:15,500 All right so here I am at my command line. 83 00:05:15,520 --> 00:05:17,550 I'm just using the one that we've installed into Adam. 84 00:05:17,560 --> 00:05:21,870 But you can do this at your terminal or command line even outside of Adam. 85 00:05:21,940 --> 00:05:24,020 We're going to do is create a new environment. 86 00:05:24,320 --> 00:05:31,340 We will say condo space create an either that name or just dash and for short. 87 00:05:31,630 --> 00:05:34,900 Then type in the name of your environment and call us environment whatever you want. 88 00:05:34,930 --> 00:05:39,730 The only thing you can't do is if you already have an environment named this you can't repeat the names. 89 00:05:39,730 --> 00:05:41,350 So we'll say my flask. 90 00:05:41,430 --> 00:05:48,840 Ian the and then will say space flask because we want flasks to be installed along with this environment 91 00:05:49,320 --> 00:05:52,490 will hit enter and it will say solving environment. 92 00:05:52,900 --> 00:05:57,330 Eventually I'll ask if you want to install a bunch of things and notice that it's installing a lot more 93 00:05:57,390 --> 00:05:58,670 than just flasks. 94 00:05:58,680 --> 00:06:03,060 And the reason for that is because flask may have some dependencies itself that it's also going to be 95 00:06:03,150 --> 00:06:03,660 installing. 96 00:06:03,660 --> 00:06:05,370 So you notice here kind of near the top. 97 00:06:05,370 --> 00:06:06,660 It's the selling Jinja too. 98 00:06:06,800 --> 00:06:09,940 So it's something that flask needs so we'll go ahead and install this. 99 00:06:10,060 --> 00:06:10,620 Why. 100 00:06:10,710 --> 00:06:15,120 And then it's going to download and extract all these packages for you and the package is going to be 101 00:06:15,120 --> 00:06:17,520 a little different depending on your operating system. 102 00:06:17,520 --> 00:06:20,360 I will jump forward in time until this is finished installing. 103 00:06:20,580 --> 00:06:25,620 OK so we jumped forward in time and we finished installing everything and now we need to activate the 104 00:06:25,620 --> 00:06:27,600 environment in order to use it. 105 00:06:27,690 --> 00:06:32,490 So to activate this environment on a Windows computer all you need to do is like it says here say activate 106 00:06:32,670 --> 00:06:34,360 and in the name of your environment. 107 00:06:34,440 --> 00:06:39,960 Now if you're using bash and that basically means if you're on a Mac OS or a Linux computer you must 108 00:06:40,020 --> 00:06:41,750 use source activate. 109 00:06:42,030 --> 00:06:47,610 So if you're on a Mac OS or Linux computer you're going to type source activates and in the name of 110 00:06:47,610 --> 00:06:48,390 your environment. 111 00:06:48,390 --> 00:06:52,130 So my flask envy since I am on a Windows computer. 112 00:06:52,170 --> 00:06:53,720 I'm just going to type activate. 113 00:06:53,750 --> 00:07:00,810 So again source is only for people using bash which is typically Mac OS and Linux users so will select 114 00:07:00,810 --> 00:07:06,720 activate my flask in V and then once it's activated you should see over here on the left hand side that 115 00:07:06,870 --> 00:07:12,150 in parentheses it says my flask in V and that basically the notes that your environment is bent has 116 00:07:12,150 --> 00:07:13,250 been activated. 117 00:07:13,290 --> 00:07:20,640 Now notice here if I see the dot dot to go back up the directory my environment is still activated and 118 00:07:20,640 --> 00:07:25,830 that basically means that I can go around my computer find different python files in my environment 119 00:07:25,830 --> 00:07:26,950 will be activated. 120 00:07:26,970 --> 00:07:34,290 So once I call Python in any location of my computer this particular version of Python is whatever particular 121 00:07:34,290 --> 00:07:37,650 version is associated with my class envy. 122 00:07:37,680 --> 00:07:42,720 So that means if I try to import other libraries maybe I try to import some pie I'll enter. 123 00:07:42,730 --> 00:07:44,260 It's going to say module not found. 124 00:07:44,310 --> 00:07:51,470 That's because we haven't installed the numpty library in my flask environment but if I type out import 125 00:07:51,540 --> 00:07:57,000 flask it's going to have no problem because we specifically requested a flask to be installed upon creating 126 00:07:57,000 --> 00:07:57,810 that environment. 127 00:07:57,960 --> 00:08:03,900 So let's type here if you ever want to add more libraries this environment all you need to do is say 128 00:08:03,900 --> 00:08:06,840 Konda install and then the name of the library. 129 00:08:06,840 --> 00:08:12,130 So if you for whatever reason wanted no imply there you would just say can install non-pay. 130 00:08:12,150 --> 00:08:17,000 The only caveat being you'd have to make sure that your environment is activated when you installed 131 00:08:17,000 --> 00:08:17,820 this. 132 00:08:18,260 --> 00:08:21,670 OK so we won't need them Pine-Sol I won't install that. 133 00:08:21,900 --> 00:08:24,270 OK and finally to deactivate the environment. 134 00:08:24,300 --> 00:08:30,960 All we need to do is type the Activate enter and you'll notice now we no longer have the print C's indicating 135 00:08:30,960 --> 00:08:35,640 that my environment is activated and again if you're a Mac OS or Linux computers you're going to want 136 00:08:35,640 --> 00:08:42,520 to type source de-activate And then if you want to reactivate the environment it will say activate my 137 00:08:42,520 --> 00:08:46,880 flask NV enter and there we have our flask environment activated. 138 00:08:47,260 --> 00:08:47,560 All right. 139 00:08:47,590 --> 00:08:52,380 So working in virtual environments definitely a big part of web development especially if Python to 140 00:08:52,390 --> 00:08:55,390 make sure that you never have any dependency issues. 141 00:08:55,480 --> 00:09:01,300 So we're going to be working with this mask or my Flast environment later on in this course. 142 00:09:01,300 --> 00:09:03,070 Thanks everyone and I'll see at the next lecture.