WEBVTT 00:00.200 --> 00:06.360 Now as we start using objects and their attributes and methods, more and more, we're going to start 00:06.360 --> 00:11.240 to see why it is that they are so useful and so loved by programmers. 00:11.760 --> 00:19.120 Now, I think one of the non-programmers that explained OOP the best is actually the late Steve Jobs, 00:19.680 --> 00:26.360 and he has this brilliant example that makes it really clear why objects are so great. 00:27.120 --> 00:34.880 In his story, he talks about this concept where let's say you were traveling to Japan and after a long 00:34.920 --> 00:40.560 flight, you finally land and you go outside and there's beautiful cherry blossoms. 00:40.560 --> 00:45.920 Mount Fuji is looking wonderful, but unfortunately, on the flight you had soiled your t shirt. 00:45.920 --> 00:52.280 You were overly eager with the tomato juice and you spilled everything on yourself. 00:52.840 --> 00:54.320 So what do we do? 00:54.840 --> 01:01.160 Well, you're in this unfamiliar city, and you have no idea even where the hell you are, let alone 01:01.220 --> 01:04.580 where to find the nearest dry cleaners or launderette. 01:04.940 --> 01:08.220 And plus, on top of that, you don't have the local currency. 01:08.420 --> 01:12.940 They take yen, but you only have pounds and you don't even speak Japanese. 01:13.220 --> 01:14.260 So what do you do? 01:14.660 --> 01:18.060 It's going to be a real struggle trying to solve this problem. 01:18.380 --> 01:20.660 Well, you're staying at a hotel, right? 01:20.700 --> 01:22.980 And the hotel staff probably speak English. 01:23.420 --> 01:29.900 So you go to the receptionist, and you tell the hotel that, hey, my t shirt is soiled, and they 01:29.900 --> 01:30.900 say, hey, no problem. 01:30.900 --> 01:35.300 We'll take that from you and we'll go and handle all of that messy stuff. 01:35.500 --> 01:37.460 We know how to find the dry cleaners. 01:37.460 --> 01:40.900 We can pay them in the local currency and we speak the local language. 01:41.220 --> 01:45.100 And what you get back is just a nice, clean t shirt. 01:45.460 --> 01:49.340 So this is similar to the process of working with objects. 01:49.660 --> 01:56.740 Essentially, if you have this hotel object which has a blueprint for how to handle dry cleaning some 01:56.780 --> 02:05.150 sort of clothing, then all you have to do is just get the object hotel and then call its associated 02:05.150 --> 02:06.550 method dry clean. 02:06.830 --> 02:10.190 And then it will do all of the messy stuff for you. 02:10.190 --> 02:14.150 And you don't have to worry about the implementation of this function at all. 02:14.750 --> 02:21.510 So now you can work with multiple objects, getting them to do different things and trust that they 02:21.510 --> 02:26.590 know how to manage their data and how to perform the necessary functionality. 02:27.310 --> 02:33.630 Coming back to a problem that we've already solved, creating that coffee machine with all of the program 02:33.630 --> 02:34.550 requirements. 02:34.790 --> 02:40.190 Well, it's time to put our object oriented programming knowledge to the test, because we're going 02:40.190 --> 02:44.270 to be making a OOP version of our coffee machine. 02:44.910 --> 02:48.590 Now, the program still has the same requirements as before. 02:48.590 --> 02:53.030 You have to print reports for all the resources you have to check. 02:53.030 --> 02:59.630 The resources are sufficient process coins, check transaction is successful, and finally make coffee. 02:59.990 --> 03:06.210 But in this case you're going to be working with objects in the course resources. 03:06.210 --> 03:11.210 You'll find a link to the starting project for the OOP coffee machine. 03:11.570 --> 03:16.530 So if you head over to this link, you can see that there's a whole bunch of code that we've already 03:16.530 --> 03:17.530 written for you. 03:17.930 --> 03:23.530 Now, the idea here is you're not going to touch any of these other files, the money machine, the 03:23.530 --> 03:25.450 menu or the coffee maker. 03:25.850 --> 03:31.210 All of that code is already been written for you, and it's almost like you're working with an external 03:31.210 --> 03:31.850 library. 03:32.170 --> 03:35.050 You're just going to trust that they do what they say they do. 03:35.930 --> 03:42.250 And you'll find a link to this coffee machine documentation that I've created, which describes in detail 03:42.410 --> 03:46.730 what each of these classes or blueprints allow you to do. 03:47.050 --> 03:53.250 So once you construct an object from the menu item class, then you have access to the name attribute, 03:53.250 --> 03:55.650 the cost attribute, ingredient attribute. 03:55.970 --> 04:00.690 And there's also descriptions of what it should do and what an example might be. 04:01.410 --> 04:07.660 You have access to all of these classes, and you can build objects from each of these classes to solve 04:07.660 --> 04:08.740 this project. 04:09.580 --> 04:14.820 In order to work with PyCharm, all you need to do is to download the zip file with all the starting 04:14.820 --> 04:16.900 code from our course resource website. 04:17.220 --> 04:22.660 Alternatively, now once you found that in your downloads folder, all you have to do is uncompress 04:22.660 --> 04:27.420 or unzip it, and then you can go into PyCharm and open it here. 04:27.420 --> 04:33.060 So click on the open button and then navigate to where you had that folder downloaded. 04:33.340 --> 04:35.580 Remember it needs to be unzipped. 04:36.340 --> 04:40.700 If you're on windows right click the zip file and choose Extract All. 04:40.980 --> 04:42.500 Then click extract. 04:42.660 --> 04:46.500 You should see an unzipped folder pop up next to your zip file. 04:47.340 --> 04:53.180 If you're on Mac, then all you need to do is just double click on the zip file. 04:53.860 --> 04:59.060 Now if we click open on that folder, then it will open up this project. 04:59.060 --> 05:03.600 And when you open up the project folder you'll see all of the same files. 05:03.920 --> 05:07.400 Now you're only going to be working from the main.py. 05:07.920 --> 05:12.920 In fact, I don't even want you to care that much about the code that's in the other files. 05:13.320 --> 05:19.040 It has class definitions and a whole bunch of other things that we're going to learn about in the next 05:19.040 --> 05:19.640 lesson. 05:19.800 --> 05:26.080 But for now, I want you to treat it as if it is an external library, which you're just going to use 05:26.680 --> 05:29.160 at the very beginning of the main.py file. 05:29.160 --> 05:35.240 I've already imported all four classes that you're going to be using menu, Menu item, Coffee Maker, 05:35.240 --> 05:36.360 and Money machine. 05:36.920 --> 05:42.480 Now all of these classes are documented in the Coffee Machine documentation website. 05:42.880 --> 05:49.520 All you have to do is head over to this website and read through what each of the classes do. 05:49.560 --> 05:54.360 Some of them have attributes and methods, others just have methods. 05:54.840 --> 06:02.280 So each of these classes have already pre-written code that do a lot of the heavy lifting and all of 06:02.410 --> 06:06.490 the code that we had to write when we wrote the coffee machine code from scratch. 06:06.930 --> 06:13.450 But this time, you're only going to be using these four classes and the objects created from them in 06:13.450 --> 06:16.650 order to achieve exactly the same goals as before. 06:17.250 --> 06:23.330 So while the goals are fresh in your mind from the previous day, you should review the code from the 06:23.330 --> 06:30.090 previous day and then have a read of the documentation and see how you would implement exactly the same 06:30.090 --> 06:35.530 project, but this time using only the objects created from these classes. 06:35.970 --> 06:40.650 You'll need to spend some time on this, because you'll need to think through how to create objects 06:40.650 --> 06:47.090 from these blueprint classes, and then how to use the objects, how to call the methods and the logic 06:47.090 --> 06:49.170 that's required to put everything together. 06:49.770 --> 06:50.570 Pause the video. 06:50.570 --> 06:57.010 Now have a think about this problem and try to make the coffee machine do exactly the same, and have 06:57.010 --> 07:02.450 all the same functionality as the coffee machine that you created in yesterday's project.