WEBVTT 00:00.480 --> 00:10.170 Now, let us go ahead and deep dive into the building blocks of objects and the classes, so we have 00:10.170 --> 00:16.880 seen a small example how we can work with groups and how is it really helpful. 00:17.130 --> 00:21.880 But now we will actually create stuff and start with the very basics. 00:22.440 --> 00:28.050 So the first thing which we will be learning about is objects now in Python. 00:28.390 --> 00:30.470 Everything is an object. 00:31.530 --> 00:41.130 So from the previous lectures, we used to have a type function that used to tell us the type of object 00:41.130 --> 00:41.820 or anything. 00:42.120 --> 00:44.650 OK, so let us have a look at this. 00:44.670 --> 00:46.260 OK, so let me print 00:49.410 --> 00:53.760 and I'll bring the type of something. 00:53.830 --> 01:02.070 OK, so let me copy this and paste this again and again for several times. 01:04.710 --> 01:08.520 OK, now first of all, let us see the type of C one. 01:09.400 --> 01:13.740 Let's see the type of full list. 01:13.970 --> 01:23.100 Let's see the type of O double, let's see a type of dictionary. 01:23.400 --> 01:26.550 So you know that this is for a list. 01:26.560 --> 01:29.260 This is for a double. 01:29.280 --> 01:30.450 This is for a dictionary. 01:30.460 --> 01:38.340 So let's run this note so you can see it shows me a class in class list, class double class dictionary. 01:38.800 --> 01:47.790 So what you get to understand from this is that all of these things are objects and how can we create 01:47.790 --> 01:48.500 an object? 01:49.190 --> 01:54.000 We can create object with the use of a key word, which is class. 01:54.270 --> 01:59.630 So to create an object, be forced upon me to create the class. 01:59.940 --> 02:03.890 So unless and until we have a class, we cannot create an object. 02:04.140 --> 02:08.550 So let's go ahead and have a look at how we can create a class. 02:08.790 --> 02:11.280 OK, now what is a class now? 02:11.280 --> 02:12.240 Class 02:15.930 --> 02:22.330 is an user defined object are created using the class keyword. 02:22.360 --> 02:26.580 So unless and until I have this class keyword, I cannot create the object. 02:26.710 --> 02:32.680 So the class is basically a blueprint that defines the nature of a future object. 02:32.940 --> 02:40.050 So if I want to create an object, I will have to define a blueprint or template from which the object 02:40.050 --> 02:40.800 will be created. 02:41.010 --> 02:47.730 OK, so here what we did, we created a blueprint of a person and using this blueprint, we created 02:47.730 --> 02:50.820 several forces, several objects of the person. 02:51.420 --> 02:51.770 Right. 02:51.930 --> 02:53.970 So we can do the same thing here. 02:54.590 --> 02:55.110 Now 02:58.020 --> 02:59.270 what is an instance? 02:59.280 --> 03:03.640 OK, now from classes we can construct different instances. 03:03.660 --> 03:08.660 So when I say Nezha going of Camonte, these are different objects. 03:08.850 --> 03:09.780 What are objects? 03:09.780 --> 03:11.760 Objects are the instances of the class. 03:11.760 --> 03:15.810 That is something the instance would you create from the blueprint. 03:16.050 --> 03:24.930 That is the object which we create from the blueprint is the instance of the class and an instance is 03:24.930 --> 03:28.120 a specific object which is created from a particular class. 03:28.320 --> 03:36.530 So when I see here Munsie instead of Morante, I would have given say or do one object to. 03:37.620 --> 03:46.650 OK, so this is a person like this, so this object one would have been the object. 03:47.700 --> 03:52.380 So this object is nothing but the instance of this person class. 03:52.620 --> 03:55.500 I'm this person class can have several. 03:59.600 --> 04:02.120 Object, it can have several instances. 04:05.660 --> 04:08.010 OK, now let's go further. 04:08.570 --> 04:13.120 So we have created a list here. 04:13.160 --> 04:17.980 We have created this list and from this list, we can create different object. 04:18.260 --> 04:21.900 So now let us go further and create a very simple object. 04:21.920 --> 04:24.030 OK, so how do we create that? 04:24.170 --> 04:25.760 So I say class. 04:26.600 --> 04:28.220 This is the key which we use. 04:28.460 --> 04:30.880 After this, I provide the name of the class. 04:31.040 --> 04:35.360 So let's say my class name is something and this is the class name. 04:35.360 --> 04:40.030 And I simply say, OK, this is the syntax of it. 04:40.370 --> 04:43.980 Now, further, I will have to give something which is related to the class. 04:44.000 --> 04:47.990 Now I will have to provide certain I prebuilt or Dimitriades in the class. 04:48.300 --> 04:49.940 OK, how do we give that. 04:50.180 --> 04:51.290 We'll see that later. 04:51.300 --> 04:57.740 But for now we will simply say, Busse, this will just deal with whatever we are doing and see how 04:57.740 --> 05:00.360 we create the methods, all the attributes later. 05:00.530 --> 05:04.520 But this is the very basic syntax offered we go for. 05:04.850 --> 05:06.180 Now this is my class. 05:07.130 --> 05:08.840 Now how do I create an object? 05:08.850 --> 05:14.360 I create an object by saying, let's say X equal to something. 05:16.070 --> 05:21.640 So now X is the object of my class sample. 05:21.980 --> 05:30.590 As simple as that, you just give the name of the object and you assign it with the class itself. 05:30.860 --> 05:35.120 OK, now if I want to print the type, I can simply say print. 05:35.780 --> 05:39.590 And I would say that if I didn't say this, I'll give X.. 05:39.860 --> 05:47.180 So now you can see that X is nothing but the object of the class stamp. 05:48.380 --> 05:51.940 OK, so X is the object of the class. 05:52.910 --> 05:58.950 Now, by convention we give the classes a name that starts with a capital letter. 05:59.030 --> 06:03.730 That is why I have given this as a capital is Hiroto. 06:03.740 --> 06:06.320 I have given it as a capital B for the person. 06:06.890 --> 06:12.190 OK, now how X is now the difference to one new instance. 06:12.440 --> 06:18.100 So whenever we are creating this sample, so X is the new reference. 06:18.230 --> 06:24.980 So whenever I want to find out or run so certain properties or get to know about different properties 06:24.980 --> 06:28.910 of the instance, right now this is creating an instance. 06:29.180 --> 06:35.390 When I see a sample it is creating an instance, but I need a variable which will actually refer to 06:35.390 --> 06:36.080 that instance. 06:36.410 --> 06:43.420 It is something like you have created a placeholder X, which contains the instance of the object class. 06:43.430 --> 06:44.650 So this is the object. 06:44.720 --> 06:46.490 So X contains the object. 06:46.700 --> 06:52.310 Now, whenever you want to refer to anything inside that, you will simply say X dot and you will put 06:52.310 --> 06:55.410 the attribute or the method name. 06:55.430 --> 07:02.430 So if I have attributes Egilsay extorted, if I have an attribute start name, I will take extort name. 07:02.810 --> 07:10.190 Now, if I have any method which I have defined, then I will have to seize the let's say, eat so egg 07:10.190 --> 07:10.820 start to eat. 07:10.820 --> 07:13.250 And to run this I have to give it with abrasives. 07:13.970 --> 07:16.010 OK, so this is how we like this. 07:17.920 --> 07:23.460 Now here we have instantiated the sample class. 07:23.900 --> 07:28.210 When we did this, we have instantiated the sample class. 07:28.460 --> 07:33.050 Now inside of the class, we currently just have this bus. 07:33.660 --> 07:35.540 OK, we don't have any methods. 07:35.540 --> 07:37.130 We don't have any attributes. 07:37.820 --> 07:42.410 We had methods and attributes here, but we don't still don't know how to write that. 07:43.640 --> 07:54.250 So let's get a photo now, we can define these methods are not revealed so we can let you create a class. 07:54.260 --> 08:01.370 OK, now for that class, any characteristic of an object is called an attribute. 08:01.670 --> 08:07.520 So when you look at this particular class, this person has a few characteristics. 08:08.180 --> 08:09.860 So what are those characteristics? 08:10.010 --> 08:11.810 The name age rule. 08:12.080 --> 08:14.630 So these are different characteristics of the person. 08:15.100 --> 08:18.140 OK, these are called attributes. 08:19.100 --> 08:21.530 Apart from that, we have methods. 08:21.710 --> 08:26.850 Now, what are method methods in operation which we can perform on the object? 08:27.380 --> 08:37.280 So this create person display person E to walk, talk, whatever the person can do is called the method. 08:38.000 --> 08:46.070 OK, so now what we will be doing is we will be creating a class called Dog, OK, and we will create 08:46.070 --> 08:48.400 certain attributes of that dog. 08:48.410 --> 08:50.870 Let's say it's a breed or its name. 08:51.260 --> 08:59.810 And apart from that, we will give certain methods of the dog, which would be, let's say, barking. 09:00.020 --> 09:03.980 So Adolphine bark so we can create something like that. 09:04.280 --> 09:09.790 OK, so let us create that and then we are creating that. 09:10.070 --> 09:15.240 So when we are talking about this, so we will have to create attributes. 09:15.440 --> 09:23.590 Now when we are creating attributes, we will use a self operate on this soil. 09:23.600 --> 09:34.280 For Breteau means when we are writing self something, this means that this object dopp the characteristic. 09:35.450 --> 09:42.240 So whatever object I'm creating, so if I have creating object one, then the particular characteristics 09:42.410 --> 09:48.620 characteristic which is associated with this object is referred to by self-taught means or self. 09:49.790 --> 09:56.960 So when I say sell dot something, it means that I am referring to something which is specific to that 09:56.960 --> 10:00.270 particular class for specific to that particular object. 10:00.500 --> 10:05.100 So I can have two hundred people or three hundred people or thousands of people. 10:05.330 --> 10:10.800 So for each and every person there will be a different name, different age, different groups. 10:11.090 --> 10:12.650 And how do I refer to that? 10:12.650 --> 10:19.270 I refer to that using the object, dog name, object, dot age, object or drooly. 10:20.570 --> 10:22.980 Let's see how we can do that. 10:24.980 --> 10:30.250 So the first thing which we will be doing is we will create a class. 10:30.560 --> 10:34.520 So we have created a class and we see dog. 10:34.580 --> 10:36.410 So this is our class dog. 10:36.800 --> 10:42.620 And previously what we have done is we simply said, boss, so this simply created the dog class. 10:43.140 --> 10:47.000 Now what we can do is we can create the function. 10:47.030 --> 10:49.180 Now there is a specific method. 10:49.460 --> 10:53.230 Whatever functions are present inside a class, they are called a method. 10:53.570 --> 11:00.620 So the first method which we have in any class is the init method. 11:00.980 --> 11:02.840 OK, how do we define that? 11:02.840 --> 11:14.430 We will see this double underscored it double in the school and it will be set by default. 11:14.990 --> 11:21.200 This is something which you will be providing it every time when you are writing this in a method. 11:21.740 --> 11:31.790 OK, and this init method, what will it do is when you are creating an object out of this class, this 11:31.790 --> 11:34.560 function will run by default. 11:35.960 --> 11:43.520 So when we saw these two functions create person and display person, we have to run these. 11:43.970 --> 11:46.850 When we created person, these did not run. 11:47.180 --> 11:49.280 We had to run these separately. 11:50.240 --> 11:51.680 We are to run these separately. 11:51.950 --> 12:00.590 But now when we are creating this đinđić, this init method will run on its own as soon as you create 12:00.740 --> 12:02.630 an instance of this class. 12:02.900 --> 12:13.460 OK, so let's run this and I'll simply print and I'll say dog created. 12:13.940 --> 12:15.860 OK, dog object created. 12:17.450 --> 12:23.810 OK, yes, I have created this sum and on these I do object. 12:24.110 --> 12:27.590 So when I run this what each objected to sink object created. 12:27.590 --> 12:28.490 Object created. 12:28.940 --> 12:32.050 So this I have done for this particular class. 12:32.420 --> 12:36.590 Now let's say I want to provide some attribute to it. 12:36.920 --> 12:38.930 OK, now what is my attribute. 12:38.930 --> 12:42.820 I want to put in that, I want to give the brain also along with. 12:43.170 --> 13:00.720 So Sabri Anayansi says dog breed is equal to breed now this breed is nothing but this one and this breed 13:01.200 --> 13:03.030 is the attribute, OK? 13:03.060 --> 13:06.600 This is the attribute I could have given any other variable also. 13:06.600 --> 13:12.360 But this is the simplest way of doing it without creating any confusion if you're using the same name 13:12.360 --> 13:12.660 here. 13:13.170 --> 13:16.560 This will actually avoid confusion, I think would have created something else. 13:16.560 --> 13:19.350 Also, I'd say breed and insiders. 13:19.350 --> 13:28.080 I can say eggs and I can put eggs and say this doesn't make a difference, but I'm reediting breed here 13:28.080 --> 13:29.760 for simplicity. 13:32.040 --> 13:35.150 OK, now this breed has been created. 13:35.400 --> 13:38.250 Now I will simply run this. 13:38.250 --> 13:44.570 So when I create some dog object, I have to provide this breed because it will be needing it. 13:45.000 --> 13:49.960 So if I run it this way, it will give me a letter saying missing one required position. 13:49.980 --> 13:53.220 Like many breeders, it is expecting me to provide a breed. 13:53.430 --> 13:56.820 So I will simply say lamb. 13:58.080 --> 14:01.020 And here I say, let's see, Husky. 14:01.720 --> 14:08.640 OK, so these are the two breeds which I have and I found this so you can see Dog Love and a husky has 14:08.640 --> 14:09.390 been created. 14:09.780 --> 14:14.130 Now, apart from this, what you can do is you can also bring the details and everything. 14:14.430 --> 14:26.880 So for granted the detail again, you can see the whole object has been created and the breed is comma. 14:27.210 --> 14:29.090 So dog breed. 14:29.280 --> 14:32.250 So wherever you will be using this attribute, right. 14:32.490 --> 14:35.070 You will be using it using the self phone. 14:36.360 --> 14:40.270 So wherever I want to use the attribute, I will see a self-portrait. 14:40.680 --> 14:45.180 This will only mean that I want to use the breed which is associated with my object. 14:45.960 --> 14:49.260 So I run this again so you can see that it is giving the breed. 14:49.270 --> 14:53.100 So I have created two different objects on these objects. 14:53.100 --> 14:56.600 Have the relevant details about this. 14:56.820 --> 14:59.430 Now I can also do something like after this. 14:59.430 --> 15:04.380 I can also see I'm not a breed, so this will give me the details. 15:04.410 --> 15:05.970 So it's saying it is lab. 15:06.300 --> 15:11.220 It is saying don't breed is Huskie, so it will give me the details accordingly. 15:11.550 --> 15:13.530 If I put print here then it'll show. 15:18.930 --> 15:20.180 So this is what we do. 15:21.320 --> 15:24.630 Now let's break down everything. 15:24.870 --> 15:28.970 So the special method in it is present here. 15:28.980 --> 15:35.320 This each attribute in a class definition begins with a reference to the instance object. 15:35.350 --> 15:38.730 OK, so everything will begin with the. 15:40.680 --> 15:41.760 Object of the. 15:43.380 --> 15:46.870 Plus, now it is by convention himself. 15:46.890 --> 15:54.840 So this is my convention given I said, OK, now here we have the breed, this breed is nothing but 15:54.840 --> 15:57.930 the argument which is giving, which we are giving inside this. 15:58.110 --> 16:02.490 So by going by convention, we are using in this way and we are putting greed inside. 16:02.490 --> 16:04.050 This was simply simplicity. 16:04.510 --> 16:11.850 OK, now the value which is parsed during the class and instantiation is this breed values. 16:11.910 --> 16:13.320 We are passing this here. 16:13.740 --> 16:17.400 That is very it is taking the value in the IT by default. 16:17.670 --> 16:23.990 I'm saving it inside this breed and running this so this init method will run by default. 16:24.000 --> 16:29.940 We don't have to do anything to run this separately if we create any other method. 16:29.940 --> 16:32.960 So to run that method, I have to run it separately. 16:33.180 --> 16:49.080 So if let's say I do something like this printer and I just put it like this and I say, print, hi, 16:49.230 --> 16:58.200 I'm pregnant, OK, so if I do it this way, so I won't get anything out of it because I am not running 16:58.200 --> 16:58.590 this. 16:58.770 --> 17:04.170 So to run this I'll have to see, see some dog print. 17:04.950 --> 17:06.980 OK then only drylands. 17:07.290 --> 17:15.930 See it is printing it now again if I want to refer to the breed I'll have to see selectivity. 17:15.960 --> 17:22.500 I just simply give it so it's not taking it because we have not used the self operator because it is 17:22.500 --> 17:23.060 not defined. 17:23.340 --> 17:26.140 So I have to give, said Dr.. 17:29.480 --> 17:31.620 Breed them. 17:32.270 --> 17:40.420 OK, now we have created two instances of the dog, Lansdorp is some unknown, OK? 17:40.640 --> 17:43.430 And they do have two different breed. 17:44.930 --> 17:50.990 OK, and these are the attributes which can be accessed using Dornberg green and some don't breed. 17:51.890 --> 17:53.450 OK, next. 17:54.320 --> 17:57.950 Now, we don't have any bad instances of the breed. 17:58.310 --> 18:05.200 OK, if you see Prenter has opened, this is up by breed, does not have a parenthesis after. 18:05.660 --> 18:11.420 OK, now these glass object attributes are the same for any instance of the class. 18:11.750 --> 18:17.670 OK, so we could create the attribute species of the for the dog. 18:17.910 --> 18:24.930 OK, now the dog's regardless of their breed, name or other attribute will always be mammals. 18:25.460 --> 18:29.590 OK, so we apply this logic in this particular manner. 18:29.600 --> 18:36.500 So we just apply this particular logic that if let's say we have something which is common to all those 18:36.890 --> 18:40.390 attributes or for all the objects of this class. 18:40.580 --> 18:47.450 So how will we do that so far that what we can simply do is we can provide something like, OK, so 18:47.450 --> 18:55.940 all the attributes will be provided inside the functions and the common ones. 18:56.310 --> 19:01.910 That is something the ladybirds or any other words which are common to all the. 19:03.910 --> 19:07.470 Objects of the class will be provided outside, OK? 19:07.690 --> 19:15.680 I can use a display and I can see the to be fuelcell so I can get the species for Don, because mammal 19:15.760 --> 19:16.620 is common for all. 19:16.840 --> 19:19.020 So I can see it for all of these. 19:20.950 --> 19:25.630 The next thing which we will all learn about is methods. 19:25.840 --> 19:29.190 So we will look that in the next session.