WEBVTT 00:00.260 --> 00:00.980 Hello guys. 00:00.980 --> 00:03.650 So we are going to continue our discussion with respect to Python. 00:03.650 --> 00:06.890 And in this video we are going to discuss about the map function. 00:06.920 --> 00:07.490 Okay. 00:07.490 --> 00:09.380 So what exactly is a map function. 00:09.380 --> 00:16.730 It applies a given function to all the items in an input list or any other iterable, and returns a 00:16.730 --> 00:18.470 map object an iterator. 00:18.500 --> 00:22.610 This is particularly useful for transforming data in list comprehensively. 00:22.670 --> 00:25.580 Now the best example to show you that. 00:25.730 --> 00:27.800 Why do we exactly use map? 00:27.800 --> 00:29.720 Let me just go ahead and write a code for you. 00:29.750 --> 00:30.260 Okay. 00:30.260 --> 00:38.090 So let's say uh, uh, I will just go ahead and define one method which is called as square. 00:38.120 --> 00:38.600 Okay. 00:38.600 --> 00:46.910 So what the square does is that it takes an input and it just multiplies, or it does a square of that 00:46.910 --> 00:50.240 specific input or it multiply it with itself. 00:50.240 --> 00:52.040 And it gives us gives us the result. 00:52.070 --> 00:52.490 Okay. 00:52.490 --> 00:58.040 So if I go ahead and try to put any number over here, let's say square of four is nothing but 16. 00:58.070 --> 01:03.080 If I go ahead and square R square of ten, then I should be getting 100 right now. 01:03.080 --> 01:04.730 This is fine right here. 01:04.730 --> 01:05.480 It's very simple. 01:05.480 --> 01:07.820 I'm just giving an input and I'm doing the square of it. 01:07.850 --> 01:08.420 Okay. 01:08.480 --> 01:16.730 Now let's say if I have a list of numbers or let's say I have a numbers in the form of list, or it 01:16.730 --> 01:18.110 can be in the form of tuple. 01:18.110 --> 01:22.340 Let's say in this particular case I have all these numbers 12345678. 01:22.370 --> 01:23.000 Okay. 01:23.570 --> 01:29.210 Now I want to apply the same operation for each and every number. 01:29.390 --> 01:33.080 One way is that I may probably give the list directly over here. 01:33.080 --> 01:35.450 Then I may put a for loop, right? 01:35.480 --> 01:40.880 I iterate through each and every element and then probably, you know, do the multiplication and append 01:40.880 --> 01:41.900 in a separate list. 01:41.930 --> 01:42.440 Right? 01:42.440 --> 01:45.560 So for doing this specific operation I need to do so many things right. 01:45.560 --> 01:50.060 I need to create an empty list and again do the append operation inside that iterate all through all 01:50.060 --> 01:51.320 this particular elements. 01:51.410 --> 01:57.650 Now instead of doing all those things, you know we can directly use map right now let me do let me 01:57.650 --> 01:59.450 show you what does map usually take. 01:59.480 --> 02:00.050 Okay. 02:00.050 --> 02:03.310 Now I want to perform this operations on all these elements. 02:03.310 --> 02:06.970 So map usually takes two input parameters. 02:07.000 --> 02:07.450 Okay. 02:07.480 --> 02:11.440 One is the function name and one is the iterable. 02:11.470 --> 02:13.120 Iterable basically means the collection. 02:13.150 --> 02:13.630 Right. 02:13.630 --> 02:16.120 So in this particular case if I'm calling map. 02:16.120 --> 02:18.730 So first parameter that I am going to give is square. 02:18.730 --> 02:20.080 So square is my function. 02:20.080 --> 02:22.210 I don't even have to use brackets over here. 02:22.330 --> 02:25.360 And the second thing that I have to give is my iterable. 02:25.360 --> 02:26.800 That is my numbers okay. 02:26.830 --> 02:31.240 So if I go ahead and execute this here, you can see that it has created a map object at this specific 02:31.240 --> 02:31.930 memory location. 02:31.960 --> 02:35.620 Now since I want let's say all the values in the form of list. 02:35.620 --> 02:38.920 So I will just go ahead and convert this into a list. 02:38.950 --> 02:39.520 Okay. 02:39.520 --> 02:41.800 So if I convert this into a list. 02:41.800 --> 02:44.320 So here you'll be able to see the output right. 02:44.350 --> 02:47.650 Now what this is going to do is that it is going to take each and every number. 02:47.680 --> 02:51.370 The map is going to take each and every number, call this particular function. 02:51.370 --> 02:55.540 And basically just for each and every number it is just going to do the square right. 02:55.570 --> 02:57.430 Now if I go ahead and see the answer. 02:57.850 --> 03:00.700 So this basically becomes my list over here. 03:00.700 --> 03:04.090 So I have to use this brackets since, uh. 03:04.120 --> 03:04.570 Okay. 03:04.570 --> 03:06.250 Now let's go ahead and see this. 03:06.250 --> 03:10.840 So here you can see for every number one, four, nine, 16, 25, 36, 49, 64. 03:10.840 --> 03:12.880 It has just squared up each and every number. 03:12.880 --> 03:16.510 So this is one basic example of using map. 03:16.510 --> 03:16.870 Right. 03:16.870 --> 03:20.950 So it applies a given function to all the items in an input list. 03:20.950 --> 03:25.060 Uh like in in this particular case it is list or it can be any other iterable. 03:25.090 --> 03:26.920 Okay now this is amazing. 03:26.920 --> 03:28.720 Let me just show you more functionalities. 03:28.720 --> 03:32.230 And this time I will be using Lambda function with map okay. 03:32.260 --> 03:35.680 Lambda function with map and obviously lambda function. 03:35.680 --> 03:39.910 You know that if there is a single expression you can just go ahead and apply lambda. 03:39.940 --> 03:40.300 Okay. 03:40.330 --> 03:41.980 So I will take the same operation. 03:41.980 --> 03:44.140 So let's say this is my numbers okay. 03:44.230 --> 03:46.060 Now how do I apply. 03:46.120 --> 03:50.530 Instead of this particular function I'll apply lambda function and I'll give the same number. 03:50.530 --> 03:52.510 So again I will go ahead and write list. 03:52.510 --> 03:54.760 And here I'm going to use the map function. 03:54.760 --> 03:57.730 The first parameter will be my lambda function. 03:57.730 --> 04:00.310 Lambda function is nothing but it is an anonymous function. 04:00.310 --> 04:02.440 So I will just go ahead and write lambda. 04:02.470 --> 04:05.320 Now what is the kind of operation that I really want to do? 04:05.320 --> 04:10.000 So input argument will be one x parameter, let's say any x parameter. 04:10.000 --> 04:13.000 And here I'm just going to multiply x into x right. 04:13.000 --> 04:18.160 And this is my entire lambda function itself right now the second parameter is nothing but my numbers 04:18.160 --> 04:18.940 which is my list. 04:18.970 --> 04:22.510 Now if I go ahead and execute it here, you'll be able to see with the help of lambda function. 04:22.510 --> 04:24.700 Also we are able to execute this okay. 04:24.730 --> 04:27.370 Now this is also very much simple very much easy. 04:27.400 --> 04:29.440 You can here you can write any kind of operation. 04:29.440 --> 04:31.180 Let's say I want to just add ten. 04:31.210 --> 04:32.140 I want to add 100. 04:32.170 --> 04:36.700 I want to do the multiplication division anything that I can I really want to do I'll be able to do 04:36.700 --> 04:36.940 it. 04:36.970 --> 04:37.510 Okay. 04:37.570 --> 04:39.580 Now let's say that okay fine. 04:39.580 --> 04:40.600 This is fine. 04:40.630 --> 04:41.020 Okay. 04:41.050 --> 04:43.810 Can we map multiple iterables. 04:43.840 --> 04:48.910 Now the question is can we map multiple iterables? 04:48.940 --> 04:49.420 Okay. 04:49.420 --> 04:51.490 And that is what we are going to discuss over here. 04:51.490 --> 04:53.890 So let me go ahead and write numbers one okay. 04:53.920 --> 04:55.180 Numbers one. 04:55.180 --> 04:57.880 And here I'm just going to create 123. 04:57.910 --> 05:01.060 And then I'm just going to write numbers. 05:01.090 --> 05:06.040 Numbers two which is equal to four five comma six. 05:06.070 --> 05:06.610 Okay. 05:07.060 --> 05:13.600 Now, since I have two iterables over here, and what I really want to do is that take each and every 05:13.600 --> 05:15.970 element from this iterable and keep on adding both of them. 05:15.970 --> 05:20.770 Let's say my final output should be a list of elements where I'll be adding the first element, second 05:20.770 --> 05:21.610 element, and third element. 05:21.610 --> 05:24.370 So my final answer should be 579. 05:24.400 --> 05:24.790 Okay. 05:24.820 --> 05:28.150 So can I do that with the help of map and lambda function. 05:28.180 --> 05:32.620 So here I'm just going to go ahead and create added underscore numbers. 05:33.190 --> 05:33.700 Okay. 05:33.700 --> 05:38.020 And here I'm going to just go ahead and use map. 05:38.170 --> 05:40.990 Along with that I'm going to use my lambda function. 05:40.990 --> 05:43.450 Let's say I'm going to take two parameters right. 05:43.480 --> 05:44.620 This will be one parameter. 05:44.650 --> 05:45.760 This will be the other parameter. 05:45.760 --> 05:47.860 So I will just go ahead and use x comma y. 05:47.860 --> 05:50.230 And now my expression will be very simple right. 05:50.230 --> 05:52.390 I'm just going to add both these numbers. 05:52.390 --> 05:54.340 So it should be x plus y right. 05:54.370 --> 05:59.530 Now the second parameter that I'm going to give is my numbers one right. 05:59.530 --> 06:01.450 So it will be my numbers one. 06:01.480 --> 06:02.770 Now second parameter. 06:02.770 --> 06:04.090 Also I can actually give right. 06:04.090 --> 06:05.940 So second parameter will be my next list. 06:05.970 --> 06:06.450 Right. 06:06.450 --> 06:09.570 So here I'm just going to go ahead and paste number two. 06:09.600 --> 06:13.200 And this all needs to be converted in list. 06:13.500 --> 06:14.130 Okay. 06:14.130 --> 06:17.850 And now if I go ahead and print my added numbers. 06:18.330 --> 06:22.290 So here you can see that I'm able to get five comma seven comma nine. 06:22.320 --> 06:22.830 Right. 06:22.830 --> 06:24.990 So this is one amazing example. 06:25.020 --> 06:30.750 Uh directly uh what I'm actually doing now there are multiple things that we can do with map. 06:30.750 --> 06:32.760 Let's show you one more operation. 06:32.760 --> 06:44.250 So here now I try to use map to convert a list of string to integers okay I'm going to do this okay. 06:44.280 --> 06:48.510 Now let's say that I have this entire code okay I'll just show you this code. 06:48.510 --> 06:49.440 Very simple. 06:49.440 --> 06:51.420 So here is my string numbers. 06:51.420 --> 06:53.880 What I'm actually doing I am just applying map. 06:53.880 --> 06:54.990 The function will be int. 06:55.020 --> 07:00.750 So typecasting is basically done on all the string underscore numbers which is in the form of list. 07:01.200 --> 07:04.410 And here you can actually see I'll be able to get the output. 07:04.410 --> 07:09.720 So there are a lot of options that you can specifically do with the help of a map again. 07:09.750 --> 07:15.390 You can use inbuilt function like int, like string, dot up or anything that you really want to do. 07:15.390 --> 07:19.830 And one thing you have to make sure whenever you are using function I don't have to use any brackets. 07:19.860 --> 07:20.070 Right. 07:20.100 --> 07:24.210 So lambda function I've called square I have called square is already defined over here. 07:24.210 --> 07:25.650 I don't have to use any brackets. 07:25.680 --> 07:26.220 Okay. 07:26.250 --> 07:32.160 Now let me just show you one more good example that how I can apply inbuilt function with the help of 07:32.160 --> 07:32.640 map. 07:32.640 --> 07:35.370 So let's say these are my words okay. 07:35.400 --> 07:37.410 The first word is apple. 07:37.410 --> 07:40.230 And let's say that this is all are in smaller character. 07:40.230 --> 07:41.670 Then I have banana. 07:41.700 --> 07:44.370 Then I have cherry. 07:44.400 --> 07:49.110 Okay, now what I'm actually going to do I'm just going to create my upper words. 07:49.110 --> 07:54.360 And here I'm going to use list of map okay. 07:54.360 --> 07:59.040 And now I know that in string there is a method is called as dot upper. 07:59.040 --> 08:05.850 And I need to apply this str dot upper on each and every words. 08:05.850 --> 08:06.330 right? 08:06.360 --> 08:07.920 So I'll just go ahead and write words. 08:07.920 --> 08:17.550 So once I do this and once I print my upper underscore words uh or word, I'll be able to see this. 08:17.580 --> 08:20.190 See apple, banana and cherry is there. 08:20.220 --> 08:20.790 Okay. 08:21.150 --> 08:24.180 Uh, let me just do one more thing. 08:24.180 --> 08:28.350 One more, uh, best thing, uh, over here, let's apply to a list of dictionary. 08:28.350 --> 08:30.540 Let's apply a map function to a list of dictionary. 08:30.540 --> 08:34.530 So I will go ahead and create a function which will be saying get underscore name. 08:34.560 --> 08:34.770 Okay. 08:34.800 --> 08:37.020 So here I will be giving my dictionary okay. 08:37.050 --> 08:38.640 This person will be a dictionary. 08:38.670 --> 08:45.300 And I will return person of name okay. 08:45.330 --> 08:48.780 Now this is fine for one dictionary item right. 08:48.780 --> 08:51.600 But what if I have a list of dictionary item. 08:51.600 --> 08:55.800 Let's say that I have a list of dictionary item which I will define over here. 08:55.800 --> 08:57.840 So let's say I will go ahead and write people. 08:57.930 --> 09:07.230 And uh, let me quickly go ahead and define over here and let me go and write name colon Okay. 09:07.260 --> 09:13.830 And name will basically be Krish comma age. 09:14.850 --> 09:24.390 Age will be nothing but a colon 32 okay, so this will be my first, uh, store name item or people 09:24.390 --> 09:24.870 item. 09:24.870 --> 09:30.690 And then let me just go ahead and say name colon is equal to Jack. 09:31.200 --> 09:31.800 Okay. 09:31.830 --> 09:36.390 And then I have the age as 33 okay. 09:36.420 --> 09:38.490 So this will be my second item okay. 09:38.670 --> 09:43.860 Now I want to perform this only not only to one item, instead all the items. 09:43.860 --> 09:44.130 Right. 09:44.130 --> 09:46.200 So let's say I have just taken two over here. 09:46.230 --> 09:47.400 Now how do I do it? 09:47.400 --> 09:48.870 First of all I will use list. 09:48.870 --> 09:50.760 Then I will use map. 09:50.760 --> 09:53.490 The map first function will be get underscore name. 09:53.520 --> 09:54.090 Okay. 09:54.180 --> 09:57.180 Then I'll be applying this to my entire iterable. 09:57.180 --> 09:59.550 And here I have list of dictionary items right. 09:59.550 --> 10:04.170 So if I go ahead and see the output here, you can see from this two records I have explored Christian 10:04.170 --> 10:04.470 Jack. 10:04.470 --> 10:07.080 And it is being given me in the form of list. 10:07.220 --> 10:07.910 right? 10:07.940 --> 10:12.050 Uh, this is one amazing things that you'll be able to see over here. 10:12.320 --> 10:17.660 Um, and, uh, at the end of the day, you can apply even multiple functions if you want. 10:17.660 --> 10:21.080 You can create multiple function, apply to the same list of elements. 10:21.080 --> 10:27.860 So in conclusion, uh, if I really want to talk about map, uh, so here, uh, one thing is that a 10:27.860 --> 10:28.970 map is used. 10:29.000 --> 10:30.620 It is used in various places. 10:30.620 --> 10:33.320 So I'll just give some kind of conclusion over here. 10:34.130 --> 10:38.450 So map function is a powerful tool for applying transformation to iterable data structures. 10:38.450 --> 10:43.250 It can be used with regular functions Lambda function, even multiple iterables providing a versatile 10:43.250 --> 10:45.050 approach to data processing in Python. 10:45.050 --> 10:48.800 So by understanding utilizing map you can write more efficient and readable code. 10:48.830 --> 10:53.990 So it is quite efficient, you know, in just single line things without iterating. 10:54.020 --> 10:56.420 You're using this particular efficient data structures. 10:56.420 --> 11:01.130 And at the end of the day, you just need to make sure your code is much more readable. 11:01.130 --> 11:03.980 The efficiency is there, performance is there with respect to this. 11:03.980 --> 11:05.630 So I hope you like this particular video. 11:05.660 --> 11:07.160 This was about maps function. 11:07.160 --> 11:08.480 I'll see you all in the next video. 11:08.480 --> 11:08.780 Thank you.