WEBVTT 1 00:00:00.400 --> 00:00:01.720 Hi guys, and welcome back. 2 00:00:01.720 --> 00:00:03.020 In this video we're going to learn 3 00:00:03.020 --> 00:00:05.000 about the object-oriented approach 4 00:00:05.000 --> 00:00:06.920 when working with matplotlib. 5 00:00:06.920 --> 00:00:09.120 Up until now, we've been using the functional approach 6 00:00:09.120 --> 00:00:13.020 where we use the plt import to basically do everything 7 00:00:13.020 --> 00:00:15.620 and everything that we do acts on the currently 8 00:00:15.620 --> 00:00:18.370 active figure or pair of axes. 9 00:00:18.370 --> 00:00:20.160 However, using the object-oriented approach, 10 00:00:20.160 --> 00:00:22.190 we can start to assign things to variables, 11 00:00:22.190 --> 00:00:24.020 and we can use them interchangeably 12 00:00:24.020 --> 00:00:26.080 in our application whenever we want. 13 00:00:26.080 --> 00:00:27.900 So we're going to learn about that in this video. 14 00:00:27.900 --> 00:00:28.800 Let's get started. 15 00:00:29.700 --> 00:00:32.210 When you're developing larger matplotlib applications, 16 00:00:32.210 --> 00:00:35.810 rather than just small scripts and using it interactively, 17 00:00:35.810 --> 00:00:37.310 the object-oriented approach can help 18 00:00:37.310 --> 00:00:39.190 make your code more explicit. 19 00:00:39.190 --> 00:00:42.320 So let's rewrite the simple line chart that we've got here 20 00:00:42.320 --> 00:00:44.610 using the object-oriented approach. 21 00:00:44.610 --> 00:00:47.510 The first thing to do is to create our figure, 22 00:00:47.510 --> 00:00:50.010 and this selects it so that other functions 23 00:00:50.010 --> 00:00:53.240 within the plt library will act upon it. 24 00:00:53.240 --> 00:00:55.740 But it's better practise, especially as I said, 25 00:00:55.740 --> 00:00:57.630 with larger applications, 26 00:00:57.630 --> 00:00:59.350 to start assigning things to variables 27 00:00:59.350 --> 00:01:01.900 so that you can use them instead of relying 28 00:01:01.900 --> 00:01:04.710 on the plt library to do things for you. 29 00:01:04.710 --> 00:01:07.250 So here we're creating the figure. 30 00:01:07.250 --> 00:01:09.530 And now we've got this figure variable, 31 00:01:09.530 --> 00:01:12.310 and we can use it to create a pair of axes. 32 00:01:12.310 --> 00:01:14.963 So we'll do figure.add subplot. 33 00:01:16.370 --> 00:01:20.870 Note that figure.add subplot does add the axes 34 00:01:20.870 --> 00:01:23.260 to the figure, but it also gives you the axes 35 00:01:23.260 --> 00:01:24.710 for you to work with. 36 00:01:24.710 --> 00:01:26.990 So now when we want to plot something 37 00:01:26.990 --> 00:01:30.800 like this line graph here, we can use axes.plot, 38 00:01:30.800 --> 00:01:33.470 and that goes into this axes. 39 00:01:33.470 --> 00:01:36.680 At the end, we do plt.show, and that is going to display 40 00:01:36.680 --> 00:01:39.100 the figure that has these axes where we've plotted 41 00:01:39.100 --> 00:01:40.932 our line chart. 42 00:01:40.932 --> 00:01:42.900 So let me run this and you'll see what comes out 43 00:01:42.900 --> 00:01:44.653 is exactly what we had before. 44 00:01:45.660 --> 00:01:48.720 Note that we're still using plt.show. 45 00:01:48.720 --> 00:01:51.690 You can normally do figure.show, 46 00:01:51.690 --> 00:01:53.430 but this will only work 47 00:01:53.430 --> 00:01:56.760 depending on which backhand you're using. 48 00:01:56.760 --> 00:01:58.960 Figure.show is great for for example, 49 00:01:58.960 --> 00:02:00.730 showing in Jupyter Notebooks 50 00:02:00.730 --> 00:02:03.530 and interactive Python interpreters and things like that, 51 00:02:03.530 --> 00:02:07.310 but plt.show will actually handle creating that window, 52 00:02:07.310 --> 00:02:09.440 let you interact with it, and so on. 53 00:02:09.440 --> 00:02:12.000 So for the most part, I recommend using plt.show, 54 00:02:12.000 --> 00:02:14.330 especially now that we are constantly running these files 55 00:02:14.330 --> 00:02:16.310 and we want to get that window to pop up. 56 00:02:16.310 --> 00:02:18.164 Almost everything that we'll do 57 00:02:18.164 --> 00:02:18.997 with the object-oriented approach, 58 00:02:18.997 --> 00:02:20.230 which is the approach that we're gonna follow 59 00:02:20.230 --> 00:02:21.930 in this section, you can do with 60 00:02:21.930 --> 00:02:23.790 the function-based approach as well. 61 00:02:23.790 --> 00:02:25.740 However, I prefer the object-oriented approach 62 00:02:25.740 --> 00:02:28.290 because I feel it produces cleaner code. 63 00:02:28.290 --> 00:02:30.890 We can set the title for each pair of axes, 64 00:02:30.890 --> 00:02:34.040 and we can do something like axes.set_title, 65 00:02:34.040 --> 00:02:35.720 and we can pass it in here. 66 00:02:35.720 --> 00:02:37.930 For example, that. 67 00:02:37.930 --> 00:02:41.110 Note that here we're interacting directly with the axes 68 00:02:41.110 --> 00:02:43.040 that we want to set the title for, 69 00:02:43.040 --> 00:02:45.440 and we're not relying on the plt library 70 00:02:45.440 --> 00:02:49.000 on having this specific pair of axes currently selected. 71 00:02:49.000 --> 00:02:54.000 We can also do things like set x label to set the labels 72 00:02:54.740 --> 00:02:59.503 and axes.set y label to set the y label axes. 73 00:03:00.530 --> 00:03:01.700 Here I'm just using test data, 74 00:03:01.700 --> 00:03:03.270 so it doesn't make too much sense 75 00:03:03.270 --> 00:03:04.830 but this is what you end up with. 76 00:03:04.830 --> 00:03:07.650 We've modified this pair of axes specifically 77 00:03:07.650 --> 00:03:09.460 and that is what this code achieves. 78 00:03:09.460 --> 00:03:10.470 So that's everything for this video, 79 00:03:10.470 --> 00:03:12.950 I just wanted to show you how it is different 80 00:03:12.950 --> 00:03:14.670 to use the object-oriented approach 81 00:03:14.670 --> 00:03:16.460 and how you'll end up interacting 82 00:03:16.460 --> 00:03:18.800 with these specific variables and objects 83 00:03:18.800 --> 00:03:20.940 rather than relying on the plt library. 84 00:03:20.940 --> 00:03:21.990 I hope you've enjoyed this video, 85 00:03:21.990 --> 00:03:24.890 thank you for joining me and I'll see you in the next one.