WEBVTT 00:00.990 --> 00:07.670 Hello, everyone, in this particular session, we will discuss about list, we will see how to create 00:07.680 --> 00:14.850 a list, how to retrieve elements of a list, how to add different objects to a list, how to insert 00:14.850 --> 00:18.900 element at a particular position, and how to remove objects from a list. 00:19.530 --> 00:22.670 We would also see how to sort the list now. 00:22.710 --> 00:25.320 First, we begin with the list. 00:25.560 --> 00:29.570 Let us discuss about the different characteristics of a list. 00:29.820 --> 00:33.750 So the first thing about list is that list is ordered in nature. 00:34.020 --> 00:40.050 Ordered in nature means that we will be able to retrieve a particular element from a particular index. 00:40.380 --> 00:42.160 Hence it is ordered in nature. 00:42.750 --> 00:44.250 Next is mutability. 00:44.460 --> 00:45.900 Now what does mutability? 00:45.900 --> 00:53.940 Mutability is a concept where a particular database allows us to change the element itself. 00:53.970 --> 00:56.900 It allows us to change a particular value. 00:57.390 --> 01:01.710 So if we talk about strings, strings are immutable in nature. 01:01.710 --> 01:02.740 How can we see that? 01:03.000 --> 01:08.400 So let's say we have a string as I try to modify a particular character. 01:08.610 --> 01:13.680 Is same at index for I want to put. 01:15.020 --> 01:21.480 Let's I want to put a character B, let's say I want to put the character so. 01:22.430 --> 01:26.340 We get the error that string object does not support an assignment. 01:26.540 --> 01:32.300 So this means that string cannot be modified, a particular index of string cannot be modified, although 01:32.420 --> 01:34.520 if you try to do something like. 01:36.520 --> 01:43.660 S is equal to be something, something so we will be able to do that not just because we are trying 01:43.660 --> 01:46.320 to replace the entire object. 01:46.330 --> 01:48.780 So here we are creating a new object. 01:48.940 --> 01:52.940 It is an entirely new strain being assigned to the variable. 01:53.590 --> 01:54.840 So this is possible. 01:55.060 --> 02:01.870 But when we try to modify a particular index of a string that is not allowed because string in itself 02:01.870 --> 02:03.690 is immutable in nature. 02:04.000 --> 02:10.390 But when we talk about list list as movable in nature, so because of that we will be able to modify 02:10.390 --> 02:10.840 a list. 02:10.850 --> 02:12.250 We will see how we can do it. 02:12.520 --> 02:13.330 But after some. 02:14.110 --> 02:18.040 Now let's see how it supports multiple data. 02:18.610 --> 02:23.640 So in case of a list, we will be able to add different type of data types. 02:23.860 --> 02:30.040 So you would have seen that in some languages it is allowed to add only one data that you can have a 02:30.040 --> 02:32.440 string or you can have a number. 02:32.650 --> 02:40.330 But in case of list invited, we will be able to add any mixture of different types. 02:40.570 --> 02:43.380 So let's first of all see how do we create the list. 02:43.570 --> 02:45.910 So first of all, we will have to give a variable. 02:46.180 --> 02:52.460 My name is Enlistee one and I want to add certain elements to it. 02:52.480 --> 02:58.450 So let the elements be string a B next element. 02:59.470 --> 03:05.290 Methe next element be one, then two, then three. 03:05.530 --> 03:08.260 Let's have another element that's true. 03:10.610 --> 03:16.850 And another element does fault, so you can see I can have different combination of values in the list. 03:17.270 --> 03:21.390 Now this is my list and just my list for you. 03:21.590 --> 03:22.850 So this is my list. 03:23.210 --> 03:31.610 Now, in case you want to retrieve a particular element from a list, we can do it by say. 03:32.840 --> 03:36.680 LSD one and I want to retrieve the zeroth index. 03:37.220 --> 03:39.660 We can do it by Elstein one zero. 03:39.890 --> 03:45.710 Let's say we want to retrieve the last element so I can do it by using minus one. 03:48.280 --> 03:53.110 Sorry, I don't have anybody, I have it is the one, so if I do a listed one, I am able to retrieve 03:53.110 --> 03:55.210 the last element, which is minus one. 03:55.570 --> 03:58.690 Now, let's say we want to retrieve NSD one. 03:58.990 --> 04:06.670 We want to retrieve the this particular element, which would be minus one, minus two, minus three. 04:07.030 --> 04:12.400 We want to retrieve the negative third element and it comes out to be three. 04:12.790 --> 04:15.780 Now, let's say we don't want to retrieve just one element. 04:15.790 --> 04:17.980 We want to retrieve multiple elements. 04:18.250 --> 04:19.350 How would we do that? 04:19.600 --> 04:22.890 We do that by saying the last one. 04:22.900 --> 04:26.230 I get that all the time and see one. 04:26.230 --> 04:34.000 And after that we say from zero the next to now, we also need to see how we can find out the entire 04:34.000 --> 04:36.700 length of a list so we can use then. 04:38.060 --> 04:43.480 And we can give amnesty one inside this, so this gives me the entire length of the middle of my list 04:43.490 --> 04:47.080 of seven so I can go up to six. 04:47.270 --> 04:51.490 So let's say six so I can see all the elements. 04:51.680 --> 04:56.830 And remember, in slicing, what happens is this is the starting point. 04:57.020 --> 05:03.260 And when I say six, this means that I want to retrieve element from zero to five. 05:03.530 --> 05:07.400 Six means that six is not supposed to be included. 05:07.560 --> 05:13.760 If you want to get all the elements, you just put nothing and retrieve all the elements. 05:14.060 --> 05:18.010 And if you give seven year, then it would give all the elements. 05:18.260 --> 05:24.230 So what you put here is the last element which you want to retrieve plus one. 05:24.250 --> 05:29.060 Always remember that this last element which you want to retrieve plus one. 05:30.930 --> 05:37.430 Now, the next thing which we can do is let's say if you want to retrieve the elements ultimately and 05:37.440 --> 05:44.400 we want to skip one element in between piquancy to this means that we want to skip one element in between. 05:44.430 --> 05:48.150 So if I retrieve this, I get the alternate values. 05:48.810 --> 05:54.780 Now, the next thing which I can do in is let's say if I want to add different objects to a list and 05:54.780 --> 05:56.720 let's say you want to combine different list. 05:56.940 --> 06:03.430 So let's create another list, say let's do it on my list or I will put in some numeric elements. 06:03.600 --> 06:06.570 One, two, three, four, five, six. 06:06.900 --> 06:15.270 And if I want to join these two list, I can simply say enlistee is equal to L'Estang one plus Amnesty 06:15.270 --> 06:15.720 two. 06:15.900 --> 06:23.480 And now if I print my list, I will give get a list, which has all the elements of list one and two. 06:23.700 --> 06:28.380 And if you see these have all the elements from list one list. 06:30.460 --> 06:40.120 What else I can do is I can also use dot up and now when they use dot up and this means that you want 06:40.120 --> 06:49.720 to add values, which are a single line, you now dot up append, always add whatever you given as an 06:49.720 --> 06:55.850 argument in just one single index, it will be added to the next index, which we have. 06:56.170 --> 07:04.470 So here, let us see the next index, let the same list one and see this one. 07:04.780 --> 07:08.500 And if you see this, do you see the length of to. 07:10.910 --> 07:19.960 So the length of two is six, so this means that we have values from zero to five already present, 07:20.210 --> 07:24.140 but there is no value on the index. 07:25.700 --> 07:35.060 Seven and six, so let's say let's do an index six, so you will see that there is no value present 07:35.060 --> 07:35.330 here. 07:35.600 --> 07:42.980 Now, if I want to add certain value, what I can do is I can simply saying this to not offend. 07:44.650 --> 07:48.050 And inside this, I won't give any object which I want to I. 07:48.370 --> 07:50.200 So let's say I want to add. 07:51.400 --> 07:53.520 Under number eighty nine. 07:56.490 --> 07:57.220 Eighty nine. 07:57.540 --> 08:02.400 And let me bring up the list to after this. 08:06.050 --> 08:13.550 So you can see the element which we added has been under that nasty mix, now, let us try one more 08:13.550 --> 08:13.820 thing. 08:13.820 --> 08:16.850 Let us try to append another list. 08:17.180 --> 08:17.870 Let us see. 08:17.870 --> 08:19.730 We tried to open the list. 08:22.290 --> 08:33.060 Of elements, eight gunmen, nine gunmen then, so now what will happen is it upend the list entirely 08:33.300 --> 08:40.890 in the next index, so it does not believe, I believe, over the elements and add them in two different 08:40.890 --> 08:41.640 indexes. 08:41.940 --> 08:47.640 It just picks out the object and puts it in the mixed index, which is available. 08:47.970 --> 08:52.980 Now, in case we don't want this thing to happen, then what we can do is. 08:54.330 --> 08:57.090 We can simply use. 08:59.720 --> 09:00.770 Extend. 09:01.730 --> 09:07.430 What extend does is let's say we want to have 11, 12. 09:09.370 --> 09:18.220 13 and 14, so what extend would do is it will I trade over this entire list and it will add the element 09:18.220 --> 09:23.530 at the end of the list and it will add them into different indexes. 09:23.800 --> 09:25.270 So let's do that. 09:25.420 --> 09:28.180 So now you see these elements were added. 09:28.190 --> 09:35.200 And one thing, the index like 11, 12, 13, 14, they have been added in two different indexes. 09:35.200 --> 09:41.560 It actually I traded on top of the list, which we provided and added the values and different elements. 09:51.280 --> 09:57.430 Now, let's try to do one more thing, let us try to instead of having this entire thing for discussion, 09:57.940 --> 09:58.900 let us try not. 09:59.200 --> 10:01.840 So let us try out a string. 10:01.840 --> 10:02.620 Try to it. 10:03.130 --> 10:05.650 OK, let me copy this. 10:06.490 --> 10:14.540 And word this fact, what we want to be had, so let me add more cells here. 10:14.560 --> 10:16.440 So now let us try this. 10:16.750 --> 10:23.220 So it added these elements in two different indexes because DLI is a string. 10:23.230 --> 10:26.280 And as we know, the string is a collection of characters. 10:26.530 --> 10:32.830 So it added I drifted over the string and added these characters one after the other one. 10:35.080 --> 10:41.400 The next thing which we can do is we can add elements of the political opposition using bought and sold. 10:41.650 --> 10:48.880 So let's say we have a list to, again, see a list to do, and we want to do it in sort. 10:49.150 --> 10:53.530 And we want to insert an element, our position C three. 10:53.830 --> 10:57.530 And the object, which we want to insert is new. 10:59.770 --> 11:03.010 And let's bring in as to do so. 11:03.010 --> 11:04.960 This is the new list. 11:05.290 --> 11:10.540 The new object has been added of the index three and how we verify index three. 11:10.540 --> 11:11.410 This is zero. 11:11.710 --> 11:13.810 One, two, three. 11:13.960 --> 11:15.610 So add the third index. 11:15.610 --> 11:17.500 This new object has been added. 11:18.010 --> 11:19.800 Now, that is another thing. 11:19.810 --> 11:23.020 Let us try to remove objects from a particular list. 11:23.020 --> 11:31.810 So to improve in to remove objects from a list, we can do enlistee, do dot remove. 11:32.140 --> 11:40.710 Now let us try to remove the element three from it, so let's try to remove three. 11:40.990 --> 11:44.110 So we will simply give three here and then print. 11:44.500 --> 11:50.710 And unless to do so, the element three has been removed from this particular list. 11:51.070 --> 11:57.100 Now another thing which we can do is we can do something we can use and see pop. 11:58.440 --> 12:05.610 So ListBox will remove the last index by default, so if I do something like. 12:07.130 --> 12:17.510 Doubtful it will remove the last element for us and it would bring down the value to us, it will return 12:17.510 --> 12:18.400 the value to us. 12:18.560 --> 12:21.070 So let us print. 12:23.230 --> 12:26.620 While you and Leather's rent. 12:29.690 --> 12:37.930 And so once we run this, it has blocked the volume from the last index, which was which was why? 12:38.510 --> 12:40.490 Because we have not given any argument. 12:40.490 --> 12:42.530 We have not given any particular index. 12:42.540 --> 12:46.040 So by default, it assumes that we want to pull from the last index. 12:46.340 --> 12:50.030 So it removes the last index from it. 12:50.420 --> 12:56.580 And the president does and the list is updated with removal of the last element. 12:57.020 --> 12:59.870 Now, apart from this, we can also do one more thing. 12:59.870 --> 13:01.820 We can do another. 13:04.040 --> 13:12.080 Index so we can provide another index save for so let's say we want to pop out index for some before 13:12.080 --> 13:13.400 popping out index for. 13:13.400 --> 13:15.630 So let's try to bring this one. 13:15.920 --> 13:20.450 So when we run this, the object from the fourth index has been removed. 13:20.460 --> 13:24.890 So zero, one, two, three, four. 13:25.010 --> 13:33.680 So the fourth index has value five index, which has been removed and the list has been updated without 13:33.860 --> 13:34.220 the. 13:35.710 --> 13:36.800 Index five. 13:38.530 --> 13:45.340 Now, the next thing which we can do is we can sort the list to sort of list, we can do something like 13:45.340 --> 13:46.240 LSD to. 13:47.120 --> 13:51.940 Don't start now when we started this particular list. 13:52.360 --> 13:58.540 Notice that we have numbers also, we have got those also and we have a list also. 13:58.720 --> 14:01.420 So it is a mix of different type of elements. 14:01.690 --> 14:07.990 So now if I try to sort the list, it gives an error because it cannot really compare these different 14:07.990 --> 14:08.850 types of lists. 14:09.130 --> 14:13.540 So let us try with another list, a simple list. 14:13.930 --> 14:16.140 So let us try this. 14:16.150 --> 14:18.310 And that is great on the list now. 14:18.790 --> 14:32.080 So let's say list for and list four letters have values like one five three seven nine and forty four 14:32.080 --> 14:38.500 and nine nine different lists and us sort this list. 14:41.070 --> 14:45.570 So once we saw this and bring the list. 14:46.450 --> 14:48.670 Sorry, list for. 14:50.360 --> 14:55.760 You can see them, this has been sorted, another thing which we can do is we can you sorted. 14:56.920 --> 15:02.110 Missed and we have option to reverse this also so I can give. 15:03.180 --> 15:12.450 List for it, and it can sort of in reverse order and give us a list, so these are different kind of 15:12.450 --> 15:16.320 methods and functions which we have list which we can use. 15:18.240 --> 15:20.830 This is what we had for this particular session. 15:21.270 --> 15:28.560 I hope you understood this in the next session, we would go through the loops and conditions. 15:28.920 --> 15:29.400 Thank you.