WEBVTT 00:00.780 --> 00:09.570 Let us now discuss about methods so methods are functions defined inside the body of a class. 00:09.960 --> 00:11.880 So this is the class. 00:12.180 --> 00:18.120 So what it will be are defining inside this, the functions which are defined inside this. 00:18.570 --> 00:20.790 These are called methods. 00:21.420 --> 00:27.260 Now, these are used to perform operations with the attributes of an object. 00:27.480 --> 00:36.120 So if I want to do certain operations, I want to print self-portrait or if I am trying to say I am 00:36.130 --> 00:36.680 Brindusa. 00:37.440 --> 00:43.590 So this is something which I'm trying to do with the attributes or if I want to modify certain that 00:43.920 --> 00:50.250 if I want to set a particular attribute, what I want to display a particular attribute or I want to 00:50.250 --> 00:56.340 do any other kind of operation, all of those things are done using these methods. 00:56.350 --> 01:08.730 Only now methods are a key concept of oops, and they are essentially used to divide the responsibilities 01:08.730 --> 01:09.980 into programming. 01:10.350 --> 01:16.650 Now, especially it is done in case of large applications, because in large applications you need a 01:16.650 --> 01:24.480 lot of structuring because then we have such large applications that are very small chunks which need 01:24.480 --> 01:27.070 to be created and then the same room together. 01:27.570 --> 01:34.080 So it is something like if you have a car, so again you will build the body will be the engine, you 01:34.080 --> 01:40.530 will put the brakes on the steering wheel and everything, and then finally you will combine them together. 01:40.530 --> 01:45.300 You will just plug them all together so that it could actually work. 01:45.780 --> 01:52.470 So these different parts which you have created, the body of the car, the engine of the car. 01:52.740 --> 01:55.050 These are different classes. 01:55.290 --> 01:57.860 So think of it as different classes. 01:58.050 --> 02:02.420 So we create all these different classes and then we combine them together. 02:02.430 --> 02:09.090 We just join them together and basically we connect them so that they can work in a better way. 02:10.590 --> 02:16.410 So this is what exactly is the use of these methods. 02:16.650 --> 02:24.840 And you can think of methods as a function which is acting on an object that takes the object itself 02:24.840 --> 02:27.420 into the account through itself argument. 02:27.570 --> 02:32.710 So what we are doing is we are basically taking the object itself. 02:32.970 --> 02:42.960 So when we talk about this self here, so if you see the name defining a particular method I'm putting 02:42.960 --> 02:47.410 in this self here, what does this mean? 02:47.550 --> 02:52.650 This means that I am trying to put in the object inside this. 02:53.700 --> 03:00.090 So I'm telling the method that, okay, this is the object which I am talking about, and you need to 03:00.090 --> 03:04.600 work on the attributes which are associated with this particular object. 03:05.070 --> 03:08.840 So this will actually help the internal. 03:08.850 --> 03:09.220 Okay. 03:09.240 --> 03:13.230 This is the object which I need to work on now, whatever I have. 03:13.260 --> 03:20.280 So if I have some bried, which I'm talking about, the GM talking about, this breed is actually belonging 03:20.280 --> 03:22.910 to the object, which I am being called for. 03:23.880 --> 03:33.090 So when I'm seeing Don Dog Breed or us, let's say assembled printer, so here the standard print of 03:33.090 --> 03:40.380 this printed function, this printer method actually gets to know that the object which it needs to 03:40.380 --> 03:42.330 work on is actually some. 03:43.410 --> 03:49.020 So whatever attribute is related to some that is, let's say here it's Labbe. 03:49.320 --> 03:57.750 So this means that this printer needs to work with the attribute which is associated with some which 03:57.750 --> 04:04.800 could be the Labrador or any other details, maybe the name of the dog, the breed of the dog, how 04:04.800 --> 04:09.800 the dog barks with the image of the dog, almost anything which is associated with the dog. 04:10.080 --> 04:19.050 The function will work on that particular thing because it has been called on the object itself. 04:20.340 --> 04:23.730 So now you understand why we actually put in the self here. 04:24.030 --> 04:29.460 If we want to put this self, the function would this method will not get to know that. 04:29.910 --> 04:32.860 What am I supposed to walk upon which I attribute? 04:32.940 --> 04:34.410 Am I supposed to work upon. 04:34.620 --> 04:40.170 So it works on the self, not any other attribute which it has. 04:40.180 --> 04:46.330 So it will get to know that, OK, if I am talking about X object then the name of X object. 04:46.330 --> 04:49.860 They need to work on the edge of this X object to work. 04:50.640 --> 04:50.960 OK. 04:52.120 --> 04:59.920 So let's get for the and let's call it something so that you get a better understanding of it. 05:00.670 --> 05:05.470 So now what we will be doing is let us create something. 05:10.070 --> 05:10.260 Didn't. 05:12.340 --> 05:15.190 Now, let me create a class. 05:19.350 --> 05:25.020 I named this class as so good, so this is my so-called class now. 05:25.050 --> 05:32.610 This class will contain by which is a constant value right now. 05:32.620 --> 05:35.730 The value of PI does not change based on the object. 05:36.030 --> 05:39.930 No matter which circle I'm creating, the value of by will still remain the same. 05:40.200 --> 05:45.180 So that is why I'll give it the value outside the method. 05:46.810 --> 05:50.040 OK, now we will be creating the circle. 05:50.040 --> 05:55.350 So whenever I'm creating the circle, I need to provide the radius to put it OK. 05:55.920 --> 05:59.150 Unless we provide the radius, this will be cannot be created. 05:59.400 --> 06:05.260 So I'm creating a diff for init function, so I'm initializing. 06:06.720 --> 06:10.270 So this is the sensation of the circle. 06:10.530 --> 06:16.890 So I am doing it with self because Salafism is a military. 06:17.220 --> 06:24.680 Then I put in the radius and I give some default value to the circle. 06:24.690 --> 06:29.840 So let's see if my user does not provide any value to the circle. 06:30.240 --> 06:35.300 If the user is not providing any radius, then my program will actually throw an error. 06:35.580 --> 06:39.090 I don't want that to happen, so I'll give it the default value to say one. 06:40.320 --> 06:43.520 And furthermore, I have to 06:47.400 --> 06:51.060 now I will instantiate the value choice itself. 06:51.450 --> 06:56.820 The radius is equal to radius. 06:57.780 --> 07:03.090 So this means that I'm giving the value of this particular value, whatever the user is providing to 07:03.090 --> 07:04.290 self-taught radius. 07:04.830 --> 07:08.840 And in case the user does not provide anything, then it takes one by default. 07:10.110 --> 07:22.470 Next, what I do is I say self taught area is equal to radius into radius in two. 07:27.060 --> 07:29.310 So good not. 07:31.650 --> 07:38.020 So when I say the so-called outby so it understands that whatever value is associated with my class 07:38.020 --> 07:41.120 Sokal, I want to access that particular value. 07:41.580 --> 07:44.440 So I'll go ahead and I will define my next function. 07:44.460 --> 07:46.690 So next function is separate. 07:46.860 --> 07:51.000 So I'm trying to set the radius or else is it radius? 07:52.650 --> 08:02.700 And I live within self again because it is a military thing and I have seen you underscore already and 08:02.700 --> 08:16.230 I go for two and I say self thought radius is equal to you radius. 08:17.070 --> 08:24.480 So what I'm doing is when I when the user will be calling said radius, the user will provide the new 08:24.480 --> 08:24.990 radius. 08:25.260 --> 08:32.130 So with the new radius I will put the value of new radius in the radius which is belonging to that particular 08:32.130 --> 08:33.920 object that I am being supported. 08:33.930 --> 08:38.100 It is right next to it to set up the area. 08:39.480 --> 08:41.250 So what will be the area. 08:41.250 --> 08:45.020 Area would be radius square in two. 08:45.420 --> 08:51.010 But I it it's so it's basically by our square. 08:51.030 --> 08:51.900 So I would say. 08:55.310 --> 09:12.430 New radios into a new year and do so don't buy or Wiggins's self-taught, buy one and the same thing. 09:13.130 --> 09:16.330 No difference you would have written. 09:16.850 --> 09:21.770 Self-taught radio is also here, then that would also have not made any difference. 09:22.970 --> 09:24.090 Just one in the same thing. 09:24.710 --> 09:29.210 Next, I'll create a method defined, so confident. 09:29.210 --> 09:32.510 So I get the 09:35.090 --> 09:42.020 parents and I put myself here because I don't need to provide anything for that. 09:42.360 --> 09:44.090 I use the existing values. 09:44.480 --> 09:47.030 So I was just written 09:49.670 --> 09:57.170 self-taught shadiest and two self-taught by. 09:59.590 --> 10:09.460 In doing so, basically, Dubai are is so confident they so this is what we have next, what we will 10:09.460 --> 10:12.980 do is we will create a surplus. 10:12.980 --> 10:15.760 So let's say my circle is see, I'm creating it. 10:16.120 --> 10:18.220 I'm just creating an object of it. 10:18.220 --> 10:19.100 So I didn't say so. 10:21.070 --> 10:22.330 And I do this. 10:22.480 --> 10:27.790 So once I do this now, so go for this circle. 10:27.790 --> 10:29.240 I'm not giving any argument. 10:29.260 --> 10:33.830 So it does by default, consider that it is equal to one right now. 10:33.880 --> 10:36.250 Let me bring my friend 10:39.070 --> 10:40.390 radius. 10:42.250 --> 10:44.470 So radius is 10:47.380 --> 10:48.920 C dot 10:51.070 --> 10:52.060 radius. 10:52.630 --> 10:54.120 Radius is not radius. 10:54.370 --> 10:57.780 So basically I'm using the object to call the attribute. 10:58.960 --> 11:03.320 Next I need to do the same for area and circumference. 11:03.730 --> 11:04.810 So I would say 11:07.960 --> 11:13.690 area is C area 11:17.260 --> 11:17.860 and. 11:24.740 --> 11:27.160 S c dot. 11:27.470 --> 11:31.950 Now, I need to call this function to get the circumference right. 11:32.360 --> 11:37.510 So I'll just get this from you and I will run this. 11:37.970 --> 11:40.950 So when I run this, I want to get the details accordingly. 11:41.600 --> 11:42.010 Right. 11:43.910 --> 11:45.240 So here I have it. 11:45.560 --> 11:51.110 So the radius comes out to be one area comes to me, three point one for circumference comes out to 11:51.110 --> 11:52.110 be six point to it. 11:52.700 --> 11:57.820 So here what we have done is we have created the instantiation function. 11:58.190 --> 12:04.430 This method will actually allow us to instantiate once this particular command is run. 12:04.730 --> 12:08.390 So once we run this, this will run by default. 12:09.470 --> 12:17.450 Then when I get these dot radius reload a.D.A, I can easily get those because these are available and 12:17.450 --> 12:19.580 these are attributes which are belonging to so good. 12:19.640 --> 12:23.120 I can easily get them for the object respectively. 12:23.130 --> 12:32.210 So if I have some other object, let me copy this and I'd just run this full circle with latitude. 12:33.010 --> 12:41.030 OK, I just run this so you can see the values are updated and I've got the new ones now again let me 12:41.030 --> 12:46.100 do this and make it as easy to OK and let me create this. 12:46.100 --> 12:47.110 I see one. 12:48.770 --> 12:56.150 So when I run this so you see we have seven we have to do now if I want to get the value for see one 12:56.150 --> 12:56.470 again. 12:56.480 --> 12:58.510 So I think this is even not area. 12:59.390 --> 13:01.210 So you see the value still exists. 13:01.370 --> 13:02.600 It has not been over. 13:12.560 --> 13:13.250 Just don't. 13:22.330 --> 13:28.730 Right now is you can see it to see one has this particular area. 13:28.780 --> 13:33.950 And same thing comes out here, right? 13:34.270 --> 13:44.380 So this is how we will be walking with these now in this anonymity here in order to calculate the area 13:44.380 --> 13:50.260 to be we we to go so blue dot by now we have done this upload by now. 13:50.270 --> 13:55.020 This is because the object does not yet have its own dot by active route. 13:55.540 --> 13:58.990 OK, because right now it has not been created. 13:59.050 --> 14:06.330 OK, once we create this once object of the circle has been created, then this attribute will come 14:06.340 --> 14:06.970 individual. 14:07.330 --> 14:07.690 Right. 14:07.960 --> 14:11.650 So we call this class object attribute fire instead. 14:11.830 --> 14:14.470 OK, so we are using this class attribute. 14:14.510 --> 14:20.670 OK, now in the set radius method, we will be working with an existing Sopel object. 14:20.680 --> 14:20.980 Right. 14:21.400 --> 14:27.400 So when we work on this one, we are already working with an existing Sobol object. 14:27.760 --> 14:29.080 We have the SILVERGLATE. 14:29.590 --> 14:31.490 So this is the reason why. 14:31.510 --> 14:44.710 Now here what happens is now we actually have a fire attribute already existing for this particular 14:44.710 --> 14:46.270 class, this object. 14:46.270 --> 14:48.670 But I'm using FF7 now. 14:48.670 --> 14:55.600 This favella will be existing, but for the very first time when I'm not creating any object at that 14:55.600 --> 15:00.700 time, the circle object is not present because of the classes when it and that is the reason why I'm 15:00.700 --> 15:01.020 using. 15:01.040 --> 15:03.550 So I'm here and I'm using Selldorff by. 15:04.730 --> 15:10.890 Fine here, you could have you so called out by also, but here, if you will be using said goodbye, 15:10.890 --> 15:11.470 it won't work. 15:11.750 --> 15:23.030 OK, OK, so let us see if we change the radius so you can see when we change the radius, things come 15:23.030 --> 15:24.260 out fine. 15:24.800 --> 15:30.680 So here you would have understood that how we use the cell operator. 15:31.280 --> 15:31.650 Right. 15:32.870 --> 15:37.440 So now let's go ahead with the inheritance. 15:37.440 --> 15:41.120 So we will be learning about inheritance in the next session. 15:41.450 --> 15:41.900 Thank you.