1 00:00:00,000 --> 00:00:00,000 Hello guys. 2 00:00:00,000 --> 00:00:03,000 So we are going to continue our discussion with respect to Python. 3 00:00:03,000 --> 00:00:06,000 And in this video we are going to discuss about the map function. 4 00:00:06,000 --> 00:00:07,000 Okay. 5 00:00:07,000 --> 00:00:09,000 So what exactly is a map function. 6 00:00:09,000 --> 00:00:16,000 It applies a given function to all the items in an input list or any other iterable, and returns a 7 00:00:16,000 --> 00:00:18,000 map object an iterator. 8 00:00:18,000 --> 00:00:22,000 This is particularly useful for transforming data in list comprehensively. 9 00:00:22,000 --> 00:00:25,000 Now, uh, the best example to show you that. 10 00:00:25,000 --> 00:00:27,000 Why do we exactly use map? 11 00:00:27,000 --> 00:00:29,000 Let me just go ahead and write a code for you. 12 00:00:29,000 --> 00:00:30,000 Okay. 13 00:00:30,000 --> 00:00:38,000 So let's say, um, uh, I will just go ahead and define one method which is called as square. 14 00:00:38,000 --> 00:00:38,000 Okay. 15 00:00:38,000 --> 00:00:46,000 So what the square does is that it takes an input and it just multiplies, or it does a square of that 16 00:00:46,000 --> 00:00:52,000 specific input or it multiply it with itself and it give us gives us the result. 17 00:00:52,000 --> 00:00:52,000 Okay. 18 00:00:52,000 --> 00:00:58,000 So if I go ahead and try to put any number over here, let's say square of four is nothing but 16. 19 00:00:58,000 --> 00:01:03,000 If I go ahead and square are square of ten, then I should be getting 100 right now. 20 00:01:03,000 --> 00:01:04,000 This is fine right here. 21 00:01:04,000 --> 00:01:05,000 It's very simple. 22 00:01:05,000 --> 00:01:07,000 I'm just giving an input and I'm doing the square of it. 23 00:01:07,000 --> 00:01:08,000 Okay. 24 00:01:08,000 --> 00:01:16,000 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 25 00:01:16,000 --> 00:01:22,000 can be in the form of tuple, let's say in this particular case I have all these numbers 12345678 okay. 26 00:01:23,000 --> 00:01:29,000 Now I want to apply the same operation for each and every number. 27 00:01:29,000 --> 00:01:33,000 One way is that I may probably give the list directly over here. 28 00:01:33,000 --> 00:01:35,000 Then I may put a for loop, right? 29 00:01:35,000 --> 00:01:40,000 I iterate through each and every element and then probably, you know, do the multiplication and append 30 00:01:40,000 --> 00:01:41,000 in a separate list. 31 00:01:41,000 --> 00:01:42,000 Right. 32 00:01:42,000 --> 00:01:45,000 So for doing this specific operation I need to do so many things right. 33 00:01:45,000 --> 00:01:50,000 I need to create an empty list and again do the append operation inside that iterate all through all 34 00:01:50,000 --> 00:01:51,000 this particular elements. 35 00:01:51,000 --> 00:01:56,000 Now instead of doing all those things you know we can directly use map right now. 36 00:01:56,000 --> 00:01:59,000 Let me do let me show you what does map usually take. 37 00:01:59,000 --> 00:01:59,000 Okay. 38 00:02:00,000 --> 00:02:03,000 Now I want to perform this operations on all these elements. 39 00:02:03,000 --> 00:02:07,000 So map usually takes two input parameters okay. 40 00:02:07,000 --> 00:02:11,000 One is the function name and one is the iterable. 41 00:02:11,000 --> 00:02:13,000 Iterable basically means the collection, right. 42 00:02:13,000 --> 00:02:16,000 So in this particular case if I'm calling map. 43 00:02:16,000 --> 00:02:18,000 So first parameter that I am going to give is square. 44 00:02:18,000 --> 00:02:20,000 So square is my function. 45 00:02:20,000 --> 00:02:22,000 I don't even have to use brackets over here. 46 00:02:22,000 --> 00:02:25,000 And the second thing that I have to give is my iterable. 47 00:02:25,000 --> 00:02:26,000 That is my numbers okay. 48 00:02:26,000 --> 00:02:31,000 So if I go ahead and execute this here, you can see that it has created a map object at this specific 49 00:02:31,000 --> 00:02:31,000 memory location. 50 00:02:31,000 --> 00:02:35,000 Now since I want, let's say all the values in the form of list. 51 00:02:35,000 --> 00:02:39,000 So I will just go ahead and convert this into a list okay. 52 00:02:39,000 --> 00:02:41,000 So if I convert this thing into a list. 53 00:02:41,000 --> 00:02:43,000 So here you'll be able to see the output. 54 00:02:43,000 --> 00:02:47,000 Right now what this is going to do is that it is going to take each and every number. 55 00:02:47,000 --> 00:02:51,000 The map is going to take each and every number, call this particular function. 56 00:02:51,000 --> 00:02:55,000 And uh, basically just for each and every number, it is just going to do the square right now if I 57 00:02:55,000 --> 00:02:57,000 go ahead and see the answer. 58 00:02:57,000 --> 00:03:00,000 So this basically becomes my list over here. 59 00:03:00,000 --> 00:03:04,000 So I have to use this brackets since uh okay. 60 00:03:04,000 --> 00:03:06,000 Now let's go ahead and see this. 61 00:03:06,000 --> 00:03:10,000 So here you can see for every number 149 16, 25, 36, 49, 64. 62 00:03:10,000 --> 00:03:12,000 It has just squared up each and every number. 63 00:03:12,000 --> 00:03:16,000 So this is one basic example of using map. 64 00:03:16,000 --> 00:03:16,000 Right. 65 00:03:16,000 --> 00:03:20,000 So it applies a given function to all the items in an input list. 66 00:03:20,000 --> 00:03:25,000 Uh like in in this particular case it is list or it can be any other iterable. 67 00:03:25,000 --> 00:03:25,000 Okay. 68 00:03:25,000 --> 00:03:26,000 Now this is amazing. 69 00:03:26,000 --> 00:03:28,000 Let me just show you more functionalities. 70 00:03:28,000 --> 00:03:32,000 And this time I will be using Lambda function with map okay. 71 00:03:32,000 --> 00:03:35,000 Lambda function with map and obviously lambda function. 72 00:03:35,000 --> 00:03:39,000 You know that if there is a single expression you can just go ahead and apply lambda. 73 00:03:39,000 --> 00:03:40,000 Okay. 74 00:03:40,000 --> 00:03:41,000 So I will take the same operation. 75 00:03:41,000 --> 00:03:44,000 So let's say this is my numbers okay. 76 00:03:44,000 --> 00:03:49,000 Now how do I apply instead of this particular function I'll apply lambda function and I'll give the 77 00:03:49,000 --> 00:03:50,000 same name number. 78 00:03:50,000 --> 00:03:52,000 So again I will go ahead and write list. 79 00:03:52,000 --> 00:03:54,000 And here I'm going to use the map function. 80 00:03:54,000 --> 00:03:57,000 The first parameter will be my lambda function. 81 00:03:57,000 --> 00:04:00,000 Lambda function is nothing but it is an anonymous function. 82 00:04:00,000 --> 00:04:02,000 So I will just go ahead and write lambda. 83 00:04:02,000 --> 00:04:05,000 Now what is the kind of operation that I really want to do? 84 00:04:05,000 --> 00:04:10,000 So input argument will be one x parameter let's say any experiment. 85 00:04:10,000 --> 00:04:12,000 And here I'm just going to multiply x into x. 86 00:04:12,000 --> 00:04:13,000 Right. 87 00:04:13,000 --> 00:04:15,000 And this is my entire lambda function itself right. 88 00:04:15,000 --> 00:04:18,000 Now the second parameter is nothing but my numbers which is my list. 89 00:04:18,000 --> 00:04:22,000 Now if I go ahead and execute it here, you'll be able to see with the help of lambda function. 90 00:04:22,000 --> 00:04:24,000 Also we are able to execute this okay. 91 00:04:24,000 --> 00:04:27,000 Now this is also very much simple very much easy. 92 00:04:27,000 --> 00:04:29,000 You can here you can write any kind of operation. 93 00:04:29,000 --> 00:04:32,000 Let's say I want to just add ten I want to add 100. 94 00:04:32,000 --> 00:04:36,000 I want to do the multiplication division anything that I can I really want to do I'll be able to do 95 00:04:36,000 --> 00:04:37,000 it okay. 96 00:04:37,000 --> 00:04:39,000 Now let's say that okay fine. 97 00:04:39,000 --> 00:04:41,000 This is fine okay. 98 00:04:41,000 --> 00:04:43,000 Can we map multiple iterables. 99 00:04:43,000 --> 00:04:48,000 Now the question is can we map multiple iterables. 100 00:04:48,000 --> 00:04:49,000 Okay. 101 00:04:49,000 --> 00:04:51,000 And that is what we are going to discuss over here. 102 00:04:51,000 --> 00:04:53,000 So let me go ahead and write numbers one okay. 103 00:04:53,000 --> 00:04:55,000 Numbers one. 104 00:04:55,000 --> 00:04:57,000 And here I'm just going to create 123. 105 00:04:57,000 --> 00:05:01,000 And then I'm just going to write numbers. 106 00:05:01,000 --> 00:05:06,000 Numbers to which is equal to four comma five comma six okay. 107 00:05:07,000 --> 00:05:10,000 Now since I have two iterables over here. 108 00:05:10,000 --> 00:05:15,000 And what I really want to do is that take each and every element from this iterable and keep on adding 109 00:05:15,000 --> 00:05:15,000 both of them. 110 00:05:15,000 --> 00:05:20,000 Let's say my final output should be a list of elements where I'll be adding the first element, second 111 00:05:20,000 --> 00:05:21,000 element, and third element. 112 00:05:21,000 --> 00:05:24,000 So my final answer should be five, seven, nine. 113 00:05:24,000 --> 00:05:28,000 Okay, so can I do that with the help of map and lambda function. 114 00:05:28,000 --> 00:05:33,000 So here I'm just going to go ahead and create added underscore numbers okay. 115 00:05:33,000 --> 00:05:37,000 And here I'm going to just go ahead and use map. 116 00:05:38,000 --> 00:05:40,000 Along with that I'm going to use my Lambda function. 117 00:05:40,000 --> 00:05:43,000 Let's say I'm going to take two parameters right. 118 00:05:43,000 --> 00:05:44,000 This will be one parameter. 119 00:05:44,000 --> 00:05:45,000 This will be the other parameter. 120 00:05:45,000 --> 00:05:47,000 So I will just go ahead and use x comma y. 121 00:05:47,000 --> 00:05:50,000 And now my expression will be very simple right. 122 00:05:50,000 --> 00:05:52,000 I'm just going to add both this number. 123 00:05:52,000 --> 00:05:59,000 So it should be x plus y right now the second parameter that I am going to give is my numbers one right. 124 00:05:59,000 --> 00:06:01,000 So it will be my numbers one. 125 00:06:01,000 --> 00:06:02,000 Now second parameter. 126 00:06:02,000 --> 00:06:04,000 Also I can actually give right. 127 00:06:04,000 --> 00:06:06,000 So second parameter will be my next list right. 128 00:06:06,000 --> 00:06:09,000 So here I'm just going to go ahead and paste number two. 129 00:06:09,000 --> 00:06:14,000 And this all needs to be converted in list Okay. 130 00:06:14,000 --> 00:06:17,000 And now if I go ahead and print my added numbers. 131 00:06:18,000 --> 00:06:22,000 So here you can see that I'm able to get five comma seven comma nine. 132 00:06:22,000 --> 00:06:22,000 Right. 133 00:06:22,000 --> 00:06:25,000 So this is one amazing example. 134 00:06:25,000 --> 00:06:30,000 Uh directly uh what I'm actually doing now there are multiple things that we can do with map. 135 00:06:30,000 --> 00:06:32,000 Let's show you one more operation. 136 00:06:32,000 --> 00:06:42,000 So here now I try to use map to convert a list of string to integers. 137 00:06:42,000 --> 00:06:44,000 Okay I'm going to do this okay. 138 00:06:44,000 --> 00:06:48,000 Now let's say that I have this entire code okay I'll just show you this code. 139 00:06:48,000 --> 00:06:49,000 Very simple. 140 00:06:49,000 --> 00:06:51,000 So here is my string numbers. 141 00:06:51,000 --> 00:06:53,000 What I'm actually doing I am just applying map. 142 00:06:53,000 --> 00:06:55,000 The function will be int. 143 00:06:55,000 --> 00:07:00,000 So typecasting is basically doing done on all the string underscore numbers which is in the form of 144 00:07:00,000 --> 00:07:00,000 list. 145 00:07:01,000 --> 00:07:04,000 And here you can actually see I'll be able to get the output. 146 00:07:04,000 --> 00:07:09,000 So there are a lot of options that you can specifically do with the help of uh map. 147 00:07:09,000 --> 00:07:15,000 Again you can use inbuilt function like int like uh string dot upper, anything that you really want 148 00:07:15,000 --> 00:07:15,000 to do. 149 00:07:15,000 --> 00:07:19,000 And one thing you have to make sure whenever you are using function I don't have to use any brackets. 150 00:07:19,000 --> 00:07:20,000 Right. 151 00:07:20,000 --> 00:07:24,000 So lambda function I've called square I have called square is already defined over here. 152 00:07:24,000 --> 00:07:25,000 I don't have to use any brackets. 153 00:07:25,000 --> 00:07:26,000 Okay. 154 00:07:26,000 --> 00:07:31,000 Now let me just show you one more, uh, good example that how I can apply inbuilt function with the 155 00:07:31,000 --> 00:07:32,000 help of map. 156 00:07:32,000 --> 00:07:35,000 So let's say these are my words okay. 157 00:07:35,000 --> 00:07:37,000 The first word is apple. 158 00:07:37,000 --> 00:07:40,000 And let's say that these all are in smaller character. 159 00:07:40,000 --> 00:07:41,000 Then I have banana. 160 00:07:41,000 --> 00:07:44,000 Then I have cherry okay. 161 00:07:45,000 --> 00:07:49,000 Now what I'm actually going to do I'm just going to create my upper words. 162 00:07:49,000 --> 00:07:53,000 And here I'm going to use list of map. 163 00:07:53,000 --> 00:07:54,000 Okay. 164 00:07:54,000 --> 00:07:59,000 And now I know that in string there is a method is called as dot upper. 165 00:07:59,000 --> 00:08:05,000 And I need to apply this str dot upper on each and every words. 166 00:08:05,000 --> 00:08:06,000 Right. 167 00:08:06,000 --> 00:08:07,000 So I'll just go ahead and write words. 168 00:08:07,000 --> 00:08:17,000 So once I do this and once I print my upper underscore words or word, I'll be able to see this. 169 00:08:17,000 --> 00:08:20,000 See apple, banana and cherry is there. 170 00:08:20,000 --> 00:08:20,000 Okay. 171 00:08:21,000 --> 00:08:24,000 Uh, let me just do one more thing. 172 00:08:24,000 --> 00:08:28,000 One more, uh, best thing, uh, over here, let's apply to a list of dictionary. 173 00:08:28,000 --> 00:08:30,000 Let's apply a map function to a list of dictionary. 174 00:08:30,000 --> 00:08:34,000 So I will go ahead and create a function which will be saying get underscore name. 175 00:08:34,000 --> 00:08:34,000 Okay. 176 00:08:34,000 --> 00:08:37,000 So here I will be giving my dictionary okay. 177 00:08:37,000 --> 00:08:44,000 This person will be a dictionary and I will return person of name. 178 00:08:44,000 --> 00:08:48,000 Okay, now this is fine for one dictionary item, right? 179 00:08:48,000 --> 00:08:51,000 But what if I have a list of dictionary item? 180 00:08:51,000 --> 00:08:55,000 Let's say that I have a list of dictionary item which I will define over here. 181 00:08:55,000 --> 00:08:57,000 So let's say I will go ahead and write people. 182 00:08:57,000 --> 00:09:06,000 And uh, let me quickly go ahead and define over here and let me go and write name colon. 183 00:09:06,000 --> 00:09:07,000 Okay. 184 00:09:07,000 --> 00:09:13,000 And uh, name will basically be crush comma age. 185 00:09:15,000 --> 00:09:18,000 Age will be nothing but uh, colon 32. 186 00:09:18,000 --> 00:09:19,000 Okay. 187 00:09:19,000 --> 00:09:24,000 So this will be my first, uh, store name item or people item. 188 00:09:24,000 --> 00:09:27,000 And then let me just go ahead and say name. 189 00:09:28,000 --> 00:09:30,000 Colon is equal to Jack. 190 00:09:31,000 --> 00:09:31,000 Okay. 191 00:09:31,000 --> 00:09:35,000 And then I have the age as 33. 192 00:09:36,000 --> 00:09:36,000 Okay. 193 00:09:36,000 --> 00:09:38,000 So this will be my second item okay. 194 00:09:38,000 --> 00:09:43,000 Now I want to perform this only not only to one item, instead all the items. 195 00:09:43,000 --> 00:09:44,000 Right. 196 00:09:44,000 --> 00:09:46,000 So let's say I have just taken two over here. 197 00:09:46,000 --> 00:09:47,000 Now how do I do it? 198 00:09:47,000 --> 00:09:48,000 First of all, I will use list. 199 00:09:48,000 --> 00:09:50,000 Then I will use map. 200 00:09:50,000 --> 00:09:53,000 The map first function will be get underscore name. 201 00:09:53,000 --> 00:09:57,000 Okay then I'll be applying this to my entire iterable. 202 00:09:57,000 --> 00:09:59,000 And here I have list of dictionary items right. 203 00:09:59,000 --> 00:10:04,000 So if I go ahead and see the output here, you can see from this two records I have explored Christian 204 00:10:04,000 --> 00:10:04,000 Jack. 205 00:10:04,000 --> 00:10:07,000 And it is being given me in the form of list. 206 00:10:07,000 --> 00:10:07,000 Right. 207 00:10:07,000 --> 00:10:12,000 Uh, this is one amazing things that you'll be able to see over here. 208 00:10:12,000 --> 00:10:17,000 Um, and uh, at the end of the day, uh, you can apply even multiple functions if you want. 209 00:10:17,000 --> 00:10:21,000 You can create multiple function apply to the same list of elements. 210 00:10:21,000 --> 00:10:27,000 So in conclusion, uh, if I really want to talk about map, uh, so here, uh, one thing is that a 211 00:10:27,000 --> 00:10:30,000 map is used, uh, it is used in various places. 212 00:10:30,000 --> 00:10:33,000 So I'll just give some kind of conclusion over here. 213 00:10:34,000 --> 00:10:38,000 So map function is a powerful tool for applying transformation to iterable data structures. 214 00:10:38,000 --> 00:10:43,000 It can be used with regular functions Lambda function, even multiple iterables providing a versatile 215 00:10:43,000 --> 00:10:45,000 approach to data processing in Python. 216 00:10:45,000 --> 00:10:48,000 So by understanding utilizing map, you can write more efficient and readable code. 217 00:10:49,000 --> 00:10:54,000 It is quite efficient, you know, in just a single line things without iterating. 218 00:10:54,000 --> 00:10:56,000 You're using this particular efficient data structures. 219 00:10:56,000 --> 00:11:01,000 And at the end of the day, you just need to make sure your code is much more readable. 220 00:11:01,000 --> 00:11:03,000 The efficiency is there, performance is there with respect to this. 221 00:11:03,000 --> 00:11:05,000 So I hope you like this particular video. 222 00:11:05,000 --> 00:11:07,000 This was about maps function. 223 00:11:07,000 --> 00:11:08,000 I'll see you in the next video. 224 00:11:08,000 --> 00:11:08,000 Thank you.