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 now we are going to start data structures in Python. 4 00:00:06,000 --> 00:00:11,000 Some of the most common data structures that are used in Python programming language are like lists, 5 00:00:11,000 --> 00:00:13,000 tuples, sets and dictionaries. 6 00:00:13,000 --> 00:00:17,000 So in this series of videos, we are probably going to discuss about all these topics. 7 00:00:17,000 --> 00:00:19,000 In this video we are going to focus more on list. 8 00:00:20,000 --> 00:00:23,000 Uh, so let me just go ahead and show you what is the video outline. 9 00:00:23,000 --> 00:00:28,000 So first of all, we will, uh, go ahead and show you how to I will go ahead and show you how to create 10 00:00:28,000 --> 00:00:29,000 a list. 11 00:00:29,000 --> 00:00:35,000 Then I will also show you accessing list items, modifying list items, some of the amazing list methods 12 00:00:35,000 --> 00:00:36,000 that we use. 13 00:00:36,000 --> 00:00:38,000 Then we have operations like slicing list. 14 00:00:39,000 --> 00:00:41,000 How do I how do we iterate over list? 15 00:00:41,000 --> 00:00:43,000 You know by using for loop and all. 16 00:00:43,000 --> 00:00:46,000 Then along with that we'll also be seeing list comprehension. 17 00:00:46,000 --> 00:00:48,000 And then we will be seeing about nested list. 18 00:00:48,000 --> 00:00:52,000 All these things will be covered with lot of practical examples. 19 00:00:52,000 --> 00:00:55,000 And I'll also be talking about what are the common errors that we will be getting. 20 00:00:55,000 --> 00:01:00,000 So before I go ahead, first of all, uh, let us go ahead and just see the definition of list. 21 00:01:00,000 --> 00:01:04,000 So here you can see list are ordered mutable collection of items. 22 00:01:04,000 --> 00:01:05,000 Right. 23 00:01:05,000 --> 00:01:07,000 Ordered mutable collection of items. 24 00:01:07,000 --> 00:01:09,000 What does mutable collection of items basically means? 25 00:01:09,000 --> 00:01:13,000 Uh, like all the items that are present in list, we can actually change it. 26 00:01:13,000 --> 00:01:14,000 Okay. 27 00:01:14,000 --> 00:01:18,000 Um, and they can contain items of different data types also. 28 00:01:18,000 --> 00:01:18,000 Right. 29 00:01:18,000 --> 00:01:22,000 So these are the two main proper properties with respect to list. 30 00:01:22,000 --> 00:01:25,000 Uh, first of all, they are ordered mutable collection of items. 31 00:01:25,000 --> 00:01:28,000 And they can contain items of different different data types. 32 00:01:28,000 --> 00:01:30,000 So let me just go ahead and let me show you that. 33 00:01:30,000 --> 00:01:32,000 How do you define a list? 34 00:01:32,000 --> 00:01:34,000 Let's say I create a variable called as list. 35 00:01:34,000 --> 00:01:37,000 And if I use this two brackets. 36 00:01:37,000 --> 00:01:40,000 And before that don't forget to select a kernel. 37 00:01:40,000 --> 00:01:43,000 So right now I've selected the kernel based on the environment that I've actually created. 38 00:01:43,000 --> 00:01:49,000 So here you can see over here when I write list with some this empty square braces. 39 00:01:49,000 --> 00:01:57,000 And if I go ahead and print the type of this variable this will give us an empty list. 40 00:01:57,000 --> 00:01:58,000 Right. 41 00:01:58,000 --> 00:02:00,000 So this is a class type of list. 42 00:02:00,000 --> 00:02:03,000 So in order to create a list it is very much simple. 43 00:02:03,000 --> 00:02:06,000 You can just use this empty brackets, right? 44 00:02:07,000 --> 00:02:12,000 Um, now if I want to add elements in the list, uh, let's say that I want to go ahead and create it. 45 00:02:12,000 --> 00:02:15,000 Like I may have multiple names over here. 46 00:02:15,000 --> 00:02:23,000 Let's say I have Krish, I have, um, Jack, I have Jacob. 47 00:02:23,000 --> 00:02:24,000 Right. 48 00:02:24,000 --> 00:02:26,000 So this is basically a list of names. 49 00:02:26,000 --> 00:02:27,000 Okay. 50 00:02:27,000 --> 00:02:31,000 I may also have other elements, like I may have one, two, three, four, five. 51 00:02:31,000 --> 00:02:33,000 Any number of elements. 52 00:02:33,000 --> 00:02:36,000 I may also have different different data types of elements over here. 53 00:02:36,000 --> 00:02:39,000 So here if I go ahead and go ahead and print names. 54 00:02:40,000 --> 00:02:44,000 So it is giving me a name error because I did not write names. 55 00:02:44,000 --> 00:02:47,000 So here you can see that I'm able to get a list of elements right. 56 00:02:47,000 --> 00:02:49,000 So this is how a list is. 57 00:02:49,000 --> 00:02:52,000 Let's say that I go ahead and create a mixed list. 58 00:02:52,000 --> 00:02:55,000 Mixed mixed underscore list list. 59 00:02:55,000 --> 00:03:02,000 And here let's say my first is a number, second is a string, third is a floating point right. 60 00:03:02,000 --> 00:03:04,000 And fourth is a Boolean variable. 61 00:03:04,000 --> 00:03:04,000 Right. 62 00:03:04,000 --> 00:03:07,000 So I may define any types of data type. 63 00:03:07,000 --> 00:03:08,000 And I may also print this. 64 00:03:08,000 --> 00:03:12,000 So let me just go ahead and print mixed underscore list. 65 00:03:12,000 --> 00:03:16,000 So I hope you got an idea about how to properly create a list of items. 66 00:03:16,000 --> 00:03:16,000 Right. 67 00:03:16,000 --> 00:03:21,000 So one is directly using this particular empty brackets. 68 00:03:21,000 --> 00:03:23,000 Or you can also go ahead and add elements over here. 69 00:03:24,000 --> 00:03:28,000 Um with respect to and any, any kind of elements, any different different data types of elements you 70 00:03:28,000 --> 00:03:29,000 can basically add. 71 00:03:29,000 --> 00:03:30,000 Okay. 72 00:03:30,000 --> 00:03:36,000 Now let's talk about accessing accessing list items. 73 00:03:36,000 --> 00:03:39,000 How do we access the list elements. 74 00:03:39,000 --> 00:03:40,000 Right. 75 00:03:40,000 --> 00:03:43,000 So let's say that I uh I create a fruits, right? 76 00:03:43,000 --> 00:03:47,000 Let's say that I'm going to create a fruits element like a list of fruits. 77 00:03:47,000 --> 00:03:49,000 Let's say like apple. 78 00:03:49,000 --> 00:04:00,000 It can be banana, it can be cherry, it can be um, kiwi. 79 00:04:00,000 --> 00:04:06,000 It can be um, pomegranate. 80 00:04:06,000 --> 00:04:06,000 Pomegranate. 81 00:04:06,000 --> 00:04:06,000 Okay. 82 00:04:07,000 --> 00:04:09,000 Or let me just write a simple. 83 00:04:10,000 --> 00:04:11,000 Okay, let's go ahead and see. 84 00:04:11,000 --> 00:04:13,000 Uh, cherries already written. 85 00:04:13,000 --> 00:04:14,000 Um, Apple. 86 00:04:14,000 --> 00:04:14,000 Banana. 87 00:04:14,000 --> 00:04:15,000 Cherry. 88 00:04:15,000 --> 00:04:16,000 Kiwi. 89 00:04:16,000 --> 00:04:17,000 Um, okay. 90 00:04:17,000 --> 00:04:20,000 I, I'm not able to remember more fruits names. 91 00:04:20,000 --> 00:04:21,000 Right. 92 00:04:21,000 --> 00:04:23,000 So let us just keep it till here, okay. 93 00:04:24,000 --> 00:04:24,000 Or. 94 00:04:24,000 --> 00:04:25,000 Okay, fine. 95 00:04:25,000 --> 00:04:27,000 I finally I got one guava. 96 00:04:27,000 --> 00:04:28,000 Right. 97 00:04:28,000 --> 00:04:31,000 So I'm just going to go ahead and create this list of elements. 98 00:04:31,000 --> 00:04:33,000 So here is my list of elements over here. 99 00:04:33,000 --> 00:04:37,000 Now uh, let's say that I want to go ahead and display Apple. 100 00:04:37,000 --> 00:04:38,000 Right. 101 00:04:38,000 --> 00:04:42,000 So in order to display it all I have to do is that just go ahead and right roots uh fruits. 102 00:04:42,000 --> 00:04:46,000 And here you can probably see that I can actually use indexing. 103 00:04:46,000 --> 00:04:46,000 Right. 104 00:04:46,000 --> 00:04:51,000 So whenever we create the elements inside a list okay. 105 00:04:51,000 --> 00:04:55,000 So here this first fruit is basically present in the zeroth index. 106 00:04:55,000 --> 00:04:56,000 Then this is present in the first index. 107 00:04:56,000 --> 00:04:57,000 Second index. 108 00:04:57,000 --> 00:04:58,000 Third index fourth index. 109 00:04:58,000 --> 00:05:04,000 So similarly all the indexes uh when I probably say all the indexes in Python starts with zero. 110 00:05:04,000 --> 00:05:09,000 If you know about our programming language, all the indexes over there starts with one number one. 111 00:05:09,000 --> 00:05:09,000 Right. 112 00:05:09,000 --> 00:05:14,000 But here we are specifically going to use um zero is the index over here. 113 00:05:14,000 --> 00:05:14,000 Right. 114 00:05:14,000 --> 00:05:18,000 But uh if I really want to just display Apple right. 115 00:05:18,000 --> 00:05:21,000 So I will just go ahead and write fruit of zero, right. 116 00:05:21,000 --> 00:05:23,000 If I'm actually trying to print this. 117 00:05:23,000 --> 00:05:26,000 So let me just go ahead and write print Fruits of Zero. 118 00:05:26,000 --> 00:05:28,000 It is not nothing but apple. 119 00:05:28,000 --> 00:05:33,000 Let's say I want to probably get fruit of uh, um in middle cherry. 120 00:05:33,000 --> 00:05:34,000 Right. 121 00:05:34,000 --> 00:05:35,000 So this will become 012. 122 00:05:35,000 --> 00:05:39,000 So if I go ahead and write fruits of two. 123 00:05:39,000 --> 00:05:42,000 So I will be able to get apple and cherry. 124 00:05:42,000 --> 00:05:45,000 And there are some amazing techniques with respect to indexing also. 125 00:05:45,000 --> 00:05:48,000 So, uh, let's say that I want to pick up guava, right? 126 00:05:48,000 --> 00:05:50,000 So I can also go ahead and write print. 127 00:05:51,000 --> 00:05:51,000 Um, yeah. 128 00:05:51,000 --> 00:05:55,000 One way is that I can go ahead and take Y01234. 129 00:05:55,000 --> 00:06:00,000 So I can probably go ahead and write fruits off fourth index I will be able to get guava. 130 00:06:00,000 --> 00:06:04,000 Now this go can also be taken through a different way. 131 00:06:04,000 --> 00:06:05,000 So let me just go ahead and write. 132 00:06:05,000 --> 00:06:09,000 So let's say that I'm going to write print of, uh, fruits. 133 00:06:10,000 --> 00:06:14,000 Let me just, uh, see and show it to you over here. 134 00:06:14,000 --> 00:06:19,000 So let me just go ahead and write Fruits of Fruits of. 135 00:06:19,000 --> 00:06:20,000 Okay. 136 00:06:20,000 --> 00:06:23,000 And now in this particular case, let me just go ahead and write minus one. 137 00:06:23,000 --> 00:06:24,000 Let's see what will happen. 138 00:06:24,000 --> 00:06:27,000 See, minus one is nothing, but it is basically talking about the last element itself. 139 00:06:27,000 --> 00:06:28,000 Right. 140 00:06:28,000 --> 00:06:30,000 So I think I should be able to get both right. 141 00:06:30,000 --> 00:06:34,000 So this is the amazing thing with respect to fruits, right. 142 00:06:34,000 --> 00:06:34,000 Uh, sorry. 143 00:06:34,000 --> 00:06:35,000 This list. 144 00:06:35,000 --> 00:06:36,000 Right. 145 00:06:36,000 --> 00:06:41,000 You are able to probably retrieve any fruit or any items inside this list just by using simple indexing. 146 00:06:41,000 --> 00:06:42,000 Okay. 147 00:06:42,000 --> 00:06:47,000 Now let me just show you one more way of printing some set of fruits elements. 148 00:06:47,000 --> 00:06:49,000 So if I go ahead and write fruits okay. 149 00:06:49,000 --> 00:06:56,000 And you know, if I just use the index one okay I'll be able to get banana. 150 00:06:56,000 --> 00:06:57,000 So I'm getting banana zero one. 151 00:06:57,000 --> 00:06:58,000 I'm getting banana over here. 152 00:06:58,000 --> 00:07:00,000 But what if I have a requirement? 153 00:07:00,000 --> 00:07:03,000 I need to get all the elements from banana till guava. 154 00:07:03,000 --> 00:07:03,000 Right. 155 00:07:03,000 --> 00:07:08,000 So if I go ahead and just make one simple change over here, right. 156 00:07:08,000 --> 00:07:11,000 What I will do, I'll say write fruits one colon. 157 00:07:11,000 --> 00:07:11,000 Right? 158 00:07:11,000 --> 00:07:18,000 One colon basically means from one first index till the end index because I'm not giving anything after 159 00:07:18,000 --> 00:07:18,000 the colon. 160 00:07:18,000 --> 00:07:23,000 So if I just go ahead and execute this here you can see banana cherry kiwi guava right. 161 00:07:23,000 --> 00:07:26,000 So this is one way right now let me do one thing. 162 00:07:26,000 --> 00:07:31,000 Let me just go ahead and print fruits one colon. 163 00:07:31,000 --> 00:07:36,000 And let's say I want to get all the elements till this kiwi index one. 164 00:07:36,000 --> 00:07:37,000 So here you have zero one. 165 00:07:37,000 --> 00:07:39,000 So right two three. 166 00:07:39,000 --> 00:07:39,000 Right. 167 00:07:39,000 --> 00:07:43,000 So now if I go ahead and write one colon three, that basically means it is just going to pick up this 168 00:07:43,000 --> 00:07:44,000 first index. 169 00:07:44,000 --> 00:07:44,000 Second index. 170 00:07:44,000 --> 00:07:46,000 It is not going to pick up the key index. 171 00:07:46,000 --> 00:07:47,000 Right. 172 00:07:47,000 --> 00:07:49,000 Uh and now if I go ahead and display it. 173 00:07:49,000 --> 00:07:51,000 So here you can see banana and cherries there. 174 00:07:51,000 --> 00:07:56,000 That basically means the third index is not getting picked up till the third index everything will get 175 00:07:56,000 --> 00:07:56,000 picked up right. 176 00:07:56,000 --> 00:07:59,000 So if I don't write any element over here. 177 00:07:59,000 --> 00:08:01,000 So it is just going to take it completely till the end. 178 00:08:01,000 --> 00:08:02,000 Right. 179 00:08:02,000 --> 00:08:07,000 And uh, here also, uh, what I can actually do, let me just go and show you one more thing. 180 00:08:07,000 --> 00:08:13,000 So if I go ahead and write, print off fruits, uh, minus one colon right now, if I go ahead and execute 181 00:08:13,000 --> 00:08:18,000 this, you can see minus one colon basically means from minus one element till colon. 182 00:08:18,000 --> 00:08:19,000 Right till colon means till the end. 183 00:08:19,000 --> 00:08:22,000 And this is just my last element over there okay. 184 00:08:22,000 --> 00:08:28,000 But if I just go ahead and write -1 or 2 let's say second index. 185 00:08:28,000 --> 00:08:35,000 So here I can see that you have to please observe here minus one is nothing but this specific element 186 00:08:35,000 --> 00:08:35,000 right. 187 00:08:35,000 --> 00:08:37,000 Two is this right. 188 00:08:37,000 --> 00:08:40,000 But I'm not talking about all these elements. 189 00:08:40,000 --> 00:08:44,000 Now if I go ahead and write minus one to -3 or -3. 190 00:08:44,000 --> 00:08:44,000 Right. 191 00:08:44,000 --> 00:08:51,000 Now here also you'll be able to see this indexing is obviously a little bit confusion okay. 192 00:08:51,000 --> 00:08:55,000 There is a little bit of confusion over here because when I'm picking up the minus one element this 193 00:08:55,000 --> 00:08:56,000 is it is giving us. 194 00:08:56,000 --> 00:08:58,000 But I'm saying from -1 to -3, right. 195 00:08:58,000 --> 00:09:00,000 So there is no such element. 196 00:09:00,000 --> 00:09:04,000 And we'll talk more about this kind of examples and how to do this kind of indexing. 197 00:09:04,000 --> 00:09:07,000 Also when we are further discussing about many things as such. 198 00:09:07,000 --> 00:09:09,000 Right, right now don't worry about this. 199 00:09:09,000 --> 00:09:11,000 Otherwise you'll get more confused over here. 200 00:09:11,000 --> 00:09:13,000 Uh, I'll just keep it like this. 201 00:09:13,000 --> 00:09:18,000 I'll remove this particular code for some time and let later on when you'll be see in the series of 202 00:09:18,000 --> 00:09:21,000 videos, will also be talking about those kind of indexing. 203 00:09:21,000 --> 00:09:21,000 Okay. 204 00:09:21,000 --> 00:09:23,000 Now, uh, perfect. 205 00:09:23,000 --> 00:09:23,000 Till here. 206 00:09:23,000 --> 00:09:26,000 I think, uh, we have, uh, learned many things over here. 207 00:09:26,000 --> 00:09:30,000 Now, what I will be showing you is that how you can modify the list elements? 208 00:09:30,000 --> 00:09:31,000 Okay. 209 00:09:31,000 --> 00:09:36,000 So let me just go ahead here and show you modifying the list elements okay. 210 00:09:36,000 --> 00:09:39,000 Now modifying the list elements is very simple. 211 00:09:39,000 --> 00:09:42,000 Let's say that I want this is my fruits right. 212 00:09:42,000 --> 00:09:48,000 So this is my fruits I want to make sure that I replace banana with something else right now. 213 00:09:48,000 --> 00:09:49,000 Banana you know it. 214 00:09:49,000 --> 00:09:50,000 It is in first index. 215 00:09:50,000 --> 00:09:51,000 Right. 216 00:09:51,000 --> 00:09:53,000 So if I go ahead and write this it is in first index. 217 00:09:53,000 --> 00:09:57,000 Let's say from this I want to probably change this into watermelon okay. 218 00:09:58,000 --> 00:10:01,000 And now I will just go ahead and print my fruits. 219 00:10:01,000 --> 00:10:02,000 Right. 220 00:10:02,000 --> 00:10:07,000 So in that specific index I'm writing watermelon over here and I'm actually displaying it. 221 00:10:07,000 --> 00:10:11,000 Now you can see my fruits has changed banana to, uh, to watermelon. 222 00:10:11,000 --> 00:10:12,000 Right. 223 00:10:12,000 --> 00:10:18,000 So this way in the indexing also, you can directly go ahead and probably replace this particular values. 224 00:10:18,000 --> 00:10:19,000 Right. 225 00:10:19,000 --> 00:10:24,000 So this is how you modify uh any elements that is present over here. 226 00:10:24,000 --> 00:10:28,000 Not only that, let's say I want to go ahead and write like this. 227 00:10:28,000 --> 00:10:30,000 Fruits okay. 228 00:10:30,000 --> 00:10:32,000 Fruits one colon okay. 229 00:10:32,000 --> 00:10:34,000 So one colon is basically giving you this answer. 230 00:10:34,000 --> 00:10:39,000 Now if I go ahead and just write here, please replace everything with watermelon. 231 00:10:39,000 --> 00:10:41,000 Now if I go ahead and see fruits. 232 00:10:41,000 --> 00:10:45,000 So here you can see uh, I'm getting this error. 233 00:10:45,000 --> 00:10:47,000 Uh let's see what is the problem. 234 00:10:47,000 --> 00:10:48,000 Uh, watermelon. 235 00:10:48,000 --> 00:10:48,000 Okay. 236 00:10:48,000 --> 00:10:54,000 Now what it has done is that from this particular index, from this particular index, it has replaced 237 00:10:54,000 --> 00:10:55,000 with this particular word. 238 00:10:55,000 --> 00:10:56,000 Right. 239 00:10:56,000 --> 00:10:59,000 But here it is not considered as a word. 240 00:10:59,000 --> 00:11:01,000 Instead, it is taking this as character by character. 241 00:11:01,000 --> 00:11:05,000 We will also be seeing how we can add word to word. 242 00:11:05,000 --> 00:11:05,000 Right? 243 00:11:05,000 --> 00:11:10,000 So in in in list you have some amazing methods like append and all. 244 00:11:10,000 --> 00:11:12,000 We'll be talking about it as we go ahead right now okay. 245 00:11:12,000 --> 00:11:14,000 Just after this section itself. 246 00:11:14,000 --> 00:11:14,000 Right. 247 00:11:14,000 --> 00:11:17,000 So this is one of the problem that we see right now. 248 00:11:17,000 --> 00:11:18,000 Let me do one thing. 249 00:11:18,000 --> 00:11:22,000 Let me again, uh, use that same fruits over here that I've actually defined. 250 00:11:23,000 --> 00:11:23,000 Okay. 251 00:11:23,000 --> 00:11:25,000 But you understood the problem. 252 00:11:25,000 --> 00:11:27,000 What has happened over here as soon as I said one colon. 253 00:11:27,000 --> 00:11:28,000 Right. 254 00:11:28,000 --> 00:11:31,000 So from first index it has just added w a t r. 255 00:11:31,000 --> 00:11:34,000 So it is not just considered this as a single word. 256 00:11:34,000 --> 00:11:37,000 Instead it is considering character by character and it is adding it. 257 00:11:37,000 --> 00:11:40,000 Okay, so let me just go ahead and define my fruits again. 258 00:11:40,000 --> 00:11:40,000 Okay. 259 00:11:40,000 --> 00:11:47,000 Now let me just go ahead and discuss more about amazing thing that is called as list methods. 260 00:11:47,000 --> 00:11:47,000 Okay. 261 00:11:48,000 --> 00:11:50,000 Now this list methods is quite beautiful. 262 00:11:50,000 --> 00:11:54,000 We'll see to it and uh, we'll be learning more about it okay. 263 00:11:54,000 --> 00:11:56,000 Now let's say I want to, as I said, right. 264 00:11:56,000 --> 00:12:02,000 I want to append an element inside this okay I want to add one element at the end let's say. 265 00:12:02,000 --> 00:12:05,000 So for this I will go ahead and write fruits dot append. 266 00:12:05,000 --> 00:12:08,000 And here let's say I want to append orange okay. 267 00:12:08,000 --> 00:12:09,000 Okay. 268 00:12:09,000 --> 00:12:14,000 Now once I write that basically means this will add an item okay. 269 00:12:14,000 --> 00:12:15,000 To the end. 270 00:12:16,000 --> 00:12:16,000 Okay. 271 00:12:16,000 --> 00:12:18,000 It will basically add an item to the end. 272 00:12:18,000 --> 00:12:19,000 Okay. 273 00:12:19,000 --> 00:12:25,000 And uh, if I just go ahead and print my fruits, you'll be able to see this. 274 00:12:25,000 --> 00:12:25,000 Right. 275 00:12:25,000 --> 00:12:31,000 So now here we'll be able to see apple, banana, cherry, kiwi, guava and oranges over here. 276 00:12:31,000 --> 00:12:31,000 Right. 277 00:12:32,000 --> 00:12:39,000 Now let's say that I have a requirement that I want to probably append any element at a specific index. 278 00:12:39,000 --> 00:12:39,000 Okay. 279 00:12:39,000 --> 00:12:50,000 So let's say I want to add, um, let's say I want to add watermelon in this first index okay. 280 00:12:50,000 --> 00:12:51,000 And right now in the first index banana is there. 281 00:12:51,000 --> 00:12:57,000 So what I will do I'll say fruits dot insert okay insert. 282 00:12:57,000 --> 00:12:59,000 Insert and I will give the index number. 283 00:12:59,000 --> 00:13:00,000 The first element will be the index number. 284 00:13:00,000 --> 00:13:05,000 And the second element will be whatever item I want to put let's say banana okay. 285 00:13:05,000 --> 00:13:09,000 And then I'm just going to print fruits. 286 00:13:10,000 --> 00:13:13,000 So here you can see apple banana banana okay. 287 00:13:13,000 --> 00:13:15,000 Banana was already there I guess. 288 00:13:15,000 --> 00:13:16,000 Yeah banana was there. 289 00:13:16,000 --> 00:13:18,000 Let me do one thing. 290 00:13:18,000 --> 00:13:21,000 Let me add watermelon also. 291 00:13:21,000 --> 00:13:21,000 Okay. 292 00:13:21,000 --> 00:13:24,000 So so in the first index I'm just going to add watermelon. 293 00:13:24,000 --> 00:13:29,000 So here you can see apple watermelon banana banana banana because I have added one time right. 294 00:13:29,000 --> 00:13:31,000 Let's say that I hate two bananas are there. 295 00:13:31,000 --> 00:13:32,000 I want to remove this. 296 00:13:32,000 --> 00:13:35,000 So I will go ahead and write fruits dot remove. 297 00:13:35,000 --> 00:13:39,000 So remove is another inbuilt function uh that is present inside this. 298 00:13:39,000 --> 00:13:41,000 So here I'm going to basically write banana okay. 299 00:13:41,000 --> 00:13:46,000 And now if I go ahead and print fruits okay. 300 00:13:46,000 --> 00:13:50,000 So here you can see banana has gone right now but we don't have one more additional banana. 301 00:13:51,000 --> 00:13:51,000 Okay. 302 00:13:52,000 --> 00:14:03,000 Uh, let's say I want to also remove and um, let's say uh, see whenever we are using this remove. 303 00:14:03,000 --> 00:14:03,000 Right. 304 00:14:03,000 --> 00:14:13,000 It is basically removing the first occurrence of an item. 305 00:14:13,000 --> 00:14:19,000 Right now, let's say I want to remove and return the last item. 306 00:14:20,000 --> 00:14:22,000 Return the last item. 307 00:14:24,000 --> 00:14:24,000 Okay. 308 00:14:26,000 --> 00:14:28,000 Let's say I want to do this. 309 00:14:28,000 --> 00:14:30,000 Uh, what do I mean by this? 310 00:14:30,000 --> 00:14:35,000 Let's say I go ahead and use one amazing inbuilt function which is called as pop. 311 00:14:35,000 --> 00:14:42,000 Okay, now pop basically means it is just going to pop the last element that is present in that particular 312 00:14:42,000 --> 00:14:42,000 fruit. 313 00:14:43,000 --> 00:14:44,000 Uh, and it is going to return us. 314 00:14:44,000 --> 00:14:45,000 Right. 315 00:14:45,000 --> 00:14:49,000 So here I'm going to write pop underscore fruit okay. 316 00:14:49,000 --> 00:14:50,000 Is equal to. 317 00:14:50,000 --> 00:14:52,000 And let me just go ahead and print it. 318 00:14:52,000 --> 00:14:54,000 So I'm going to print it over here. 319 00:14:54,000 --> 00:14:58,000 And let me just go ahead and write pop fruits okay. 320 00:14:58,000 --> 00:15:00,000 And, uh, let me just print it. 321 00:15:00,000 --> 00:15:00,000 Okay. 322 00:15:00,000 --> 00:15:02,000 Let's, uh. 323 00:15:02,000 --> 00:15:07,000 Because at the end of the day, once, I probably, uh, print this and I'll also print the remaining 324 00:15:07,000 --> 00:15:09,000 items that are there in the fruits. 325 00:15:10,000 --> 00:15:10,000 Okay. 326 00:15:10,000 --> 00:15:12,000 So here you can see orange has been popped. 327 00:15:12,000 --> 00:15:12,000 Why? 328 00:15:12,000 --> 00:15:16,000 Because the last element in this list of fruits was orange. 329 00:15:16,000 --> 00:15:20,000 When orange was popped from this particular orange got removed. 330 00:15:20,000 --> 00:15:23,000 Okay, remove and return the last element. 331 00:15:24,000 --> 00:15:25,000 That is how you can specifically do it. 332 00:15:25,000 --> 00:15:28,000 And for that we use an inbuilt function called as pop. 333 00:15:28,000 --> 00:15:36,000 Okay, now let's say that I want to get an index of any fruit right based on the name of the fruit. 334 00:15:36,000 --> 00:15:39,000 So if I go ahead and write fruits dot index. 335 00:15:39,000 --> 00:15:46,000 And here let's say that I want to use, uh, cherry, I want to get the index of the fruit called a 336 00:15:46,000 --> 00:15:47,000 cherry. 337 00:15:47,000 --> 00:15:47,000 Okay. 338 00:15:47,000 --> 00:15:48,000 Cherry. 339 00:15:48,000 --> 00:15:51,000 And this will basically be my index. 340 00:15:52,000 --> 00:15:55,000 And let me just go ahead and print the index. 341 00:15:57,000 --> 00:16:02,000 Now, if I go ahead and execute, you can see that cherry is basically present in 012 three third index. 342 00:16:02,000 --> 00:16:05,000 So I am able to get the output okay. 343 00:16:05,000 --> 00:16:09,000 Uh, again one more thing is that, uh, let me just go ahead and do one thing. 344 00:16:09,000 --> 00:16:16,000 Fruit fruit dot append, or I will try to insert in the second index. 345 00:16:16,000 --> 00:16:18,000 Banana okay. 346 00:16:19,000 --> 00:16:20,000 Banana is already there. 347 00:16:20,000 --> 00:16:24,000 And now let me do one one more inbuilt function. 348 00:16:24,000 --> 00:16:26,000 I'll just go ahead and write fruit dot count. 349 00:16:26,000 --> 00:16:28,000 And here I will just go ahead and write. 350 00:16:28,000 --> 00:16:30,000 Sorry, it should be count. 351 00:16:30,000 --> 00:16:34,000 I will just go ahead and write banana okay. 352 00:16:34,000 --> 00:16:34,000 Okay. 353 00:16:34,000 --> 00:16:37,000 And let me just print this. 354 00:16:37,000 --> 00:16:37,000 Okay. 355 00:16:38,000 --> 00:16:43,000 Now what is going to happen is that you'll be able to see it will just count the number of elements. 356 00:16:43,000 --> 00:16:50,000 And obviously after inserting this banana right now, if you see inside my fruits there are two bananas, 357 00:16:50,000 --> 00:16:50,000 right? 358 00:16:50,000 --> 00:16:51,000 Banana and banana. 359 00:16:51,000 --> 00:16:52,000 So it is just counting that. 360 00:16:52,000 --> 00:16:57,000 How many number of items this specific uh, in this particular list it is there, right. 361 00:16:58,000 --> 00:17:04,000 So here I'm just showing you different, different inbuilt function just by using a list of items. 362 00:17:04,000 --> 00:17:08,000 And uh, here you can see I've shown you a lot of coding with respect to this okay. 363 00:17:09,000 --> 00:17:11,000 Now I may also do something like this. 364 00:17:11,000 --> 00:17:13,000 I may sort this entire list of items. 365 00:17:13,000 --> 00:17:16,000 So if I go ahead and write fruits dot sort. 366 00:17:16,000 --> 00:17:18,000 So here you'll be able to see. 367 00:17:18,000 --> 00:17:23,000 Now if I go ahead and print this fruits you'll be seeing apple banana Banana. 368 00:17:23,000 --> 00:17:23,000 Cherry. 369 00:17:23,000 --> 00:17:24,000 Guava. 370 00:17:24,000 --> 00:17:24,000 Kiwi. 371 00:17:24,000 --> 00:17:25,000 Watermelon. 372 00:17:25,000 --> 00:17:27,000 So automatically based on. 373 00:17:27,000 --> 00:17:36,000 So in in short this will this will sort the list in ascending order. 374 00:17:36,000 --> 00:17:37,000 Okay. 375 00:17:37,000 --> 00:17:39,000 It is just going to sort all the list in ascending order. 376 00:17:39,000 --> 00:17:45,000 And finally here you have fruits dot reverse reverse in another function which will reverse all the 377 00:17:45,000 --> 00:17:46,000 elements over here. 378 00:17:46,000 --> 00:17:52,000 Now if I go ahead and do this right now, you can see the all the list of the elements will basically 379 00:17:52,000 --> 00:17:53,000 get reversed, right? 380 00:17:53,000 --> 00:17:58,000 So this is nothing, but it reverse says the list. 381 00:17:58,000 --> 00:17:59,000 Okay. 382 00:17:59,000 --> 00:18:04,000 And just I'm showing you what all different different inbuilt functions are basically present over here. 383 00:18:04,000 --> 00:18:05,000 Okay. 384 00:18:05,000 --> 00:18:11,000 And then uh, finally if I want to clear the entire list I can go ahead and write fruits dot. 385 00:18:11,000 --> 00:18:11,000 Clear. 386 00:18:11,000 --> 00:18:11,000 clear. 387 00:18:12,000 --> 00:18:12,000 Right. 388 00:18:12,000 --> 00:18:15,000 And now if I use this inbuilt function. 389 00:18:15,000 --> 00:18:21,000 So this will remove all items from the list. 390 00:18:22,000 --> 00:18:22,000 Okay. 391 00:18:22,000 --> 00:18:25,000 Now if I go ahead and print fruits. 392 00:18:26,000 --> 00:18:29,000 So here you can see I'm getting an empty list. 393 00:18:29,000 --> 00:18:34,000 So till now we have discussed about mainly uh, if uh, if I go ahead and show you with respect to the 394 00:18:34,000 --> 00:18:39,000 video outline, uh, we have understood about creating list, accessing list items, modifying list 395 00:18:39,000 --> 00:18:40,000 elements. 396 00:18:40,000 --> 00:18:42,000 Uh, then we discussed about list methods. 397 00:18:42,000 --> 00:18:44,000 Now we are going to discuss about slicing list. 398 00:18:44,000 --> 00:18:48,000 So let's go ahead and discuss more about slicing list. 399 00:18:50,000 --> 00:18:53,000 So guys now let's go ahead and talk more about slicing lists. 400 00:18:53,000 --> 00:18:57,000 So before that I will go ahead and make some cells. 401 00:18:57,000 --> 00:18:58,000 Uh so there is a shortcut. 402 00:18:58,000 --> 00:19:04,000 Just press escape and a you will be able to create as many number of cells as you want. 403 00:19:04,000 --> 00:19:04,000 Okay. 404 00:19:04,000 --> 00:19:10,000 Now what I'm actually going to do is that I am just going to take this numbers. 405 00:19:10,000 --> 00:19:10,000 Okay. 406 00:19:10,000 --> 00:19:14,000 So I'm defining these numbers 123456789 ten. 407 00:19:14,000 --> 00:19:17,000 Now I will just go ahead and write some print elements. 408 00:19:17,000 --> 00:19:23,000 Let's say print numbers two colon five okay. 409 00:19:23,000 --> 00:19:28,000 now let's talk about more numbers. 410 00:19:30,000 --> 00:19:30,000 Oops. 411 00:19:34,000 --> 00:19:36,000 Colon five okay. 412 00:19:37,000 --> 00:19:39,000 Okay I didn't close this brackets. 413 00:19:39,000 --> 00:19:41,000 So that is the reason it was giving me an error. 414 00:19:41,000 --> 00:19:42,000 No worries. 415 00:19:43,000 --> 00:19:48,000 Now we'll go ahead and write print numbers five colon. 416 00:19:48,000 --> 00:19:54,000 And along with this we will also go ahead and see print numbers. 417 00:19:55,000 --> 00:19:59,000 Double colon two okay double colon. 418 00:19:59,000 --> 00:20:01,000 So here we are also learning about double colon. 419 00:20:01,000 --> 00:20:03,000 Single colon I've just given you an idea about it. 420 00:20:03,000 --> 00:20:05,000 But we'll also see with respect to double colon. 421 00:20:05,000 --> 00:20:13,000 And then we'll also go ahead and print our numbers double Double colon minus one. 422 00:20:13,000 --> 00:20:14,000 Okay. 423 00:20:14,000 --> 00:20:21,000 Now just pause for a second and just try to imagine in your mind like what will be the specific outputs 424 00:20:21,000 --> 00:20:22,000 okay. 425 00:20:22,000 --> 00:20:24,000 And then we will discuss further okay. 426 00:20:24,000 --> 00:20:26,000 So here you can see two colon five. 427 00:20:26,000 --> 00:20:29,000 It is very simple 012 from 2 to 5 elements. 428 00:20:29,000 --> 00:20:35,000 So two uh 345 is basically getting displayed 012345. 429 00:20:35,000 --> 00:20:37,000 So this three elements will get displayed. 430 00:20:37,000 --> 00:20:40,000 Colon 512345 will get displayed. 431 00:20:40,000 --> 00:20:42,000 So it is basically coming over here till five. 432 00:20:42,000 --> 00:20:46,000 Then you have 6789 from five colon to till the end. 433 00:20:46,000 --> 00:20:48,000 Now this is very much important. 434 00:20:48,000 --> 00:20:49,000 Double colon two. 435 00:20:49,000 --> 00:20:51,000 What does this basically mean. 436 00:20:51,000 --> 00:20:55,000 And double colon two basically means from all the elements from first. 437 00:20:55,000 --> 00:20:58,000 And this two will be taken as a step size. 438 00:20:58,000 --> 00:20:58,000 Right. 439 00:20:58,000 --> 00:21:01,000 So we will jump two steps ahead. 440 00:21:01,000 --> 00:21:04,000 Like from here we'll jump one two then three will get displayed again. 441 00:21:04,000 --> 00:21:06,000 Jump two steps five will display from again. 442 00:21:06,000 --> 00:21:10,000 From this jump to two steps, seven will get displayed again. 443 00:21:10,000 --> 00:21:10,000 Jump over here. 444 00:21:10,000 --> 00:21:12,000 Nine will be getting displayed. 445 00:21:12,000 --> 00:21:13,000 So double colon. 446 00:21:13,000 --> 00:21:16,000 See if I really want to make you understand about double colon. 447 00:21:16,000 --> 00:21:18,000 So I will go ahead and write double colon. 448 00:21:18,000 --> 00:21:20,000 Double colon basically means all the elements. 449 00:21:20,000 --> 00:21:23,000 Right now if I am writing okay fine. 450 00:21:23,000 --> 00:21:26,000 Uh let's give the test step sizes one. 451 00:21:26,000 --> 00:21:26,000 Then. 452 00:21:26,000 --> 00:21:29,000 Also, I'll be getting the same output if I give the step size to two. 453 00:21:29,000 --> 00:21:31,000 So double jumps will be happening. 454 00:21:31,000 --> 00:21:31,000 Right? 455 00:21:31,000 --> 00:21:33,000 This is basically the step size. 456 00:21:33,000 --> 00:21:40,000 Then if I write three then again three steps like from here one two jump and third uh whichever will 457 00:21:40,000 --> 00:21:41,000 be the element that will get displayed. 458 00:21:41,000 --> 00:21:42,000 So four 710 right. 459 00:21:42,000 --> 00:21:44,000 So I hope you got an idea about it. 460 00:21:44,000 --> 00:21:47,000 Now double colon one basically means what. 461 00:21:47,000 --> 00:21:47,000 Okay. 462 00:21:47,000 --> 00:21:52,000 So double colon one double colon is nothing, but it is all the elements minus one okay. 463 00:21:52,000 --> 00:21:55,000 From previous take all the elements one by one and display it. 464 00:21:55,000 --> 00:21:58,000 If I go ahead and again write something like this. 465 00:21:58,000 --> 00:22:01,000 Let's say I go ahead and write numbers okay. 466 00:22:01,000 --> 00:22:03,000 Double colon minus two. 467 00:22:03,000 --> 00:22:06,000 Write some form back every two numbers. 468 00:22:06,000 --> 00:22:06,000 Right. 469 00:22:06,000 --> 00:22:09,000 It will skip every one number and display the other number over here. 470 00:22:09,000 --> 00:22:10,000 Right. 471 00:22:10,000 --> 00:22:12,000 So this is basically called as a slicing. 472 00:22:12,000 --> 00:22:13,000 And uh. 473 00:22:13,000 --> 00:22:15,000 Uh, some of the operations will be involved in slicing. 474 00:22:15,000 --> 00:22:21,000 Whenever we want to retrieve some results we want to modify them, do something right so we can actually 475 00:22:21,000 --> 00:22:27,000 use it right now coming to the next thing is iterating over list. 476 00:22:27,000 --> 00:22:28,000 Okay. 477 00:22:28,000 --> 00:22:31,000 Now I have already shown you how to iterate over strings. 478 00:22:31,000 --> 00:22:35,000 Similarly you can also iterate over list, right? 479 00:22:35,000 --> 00:22:38,000 So for that also again I will be going and using for loop. 480 00:22:38,000 --> 00:22:43,000 Let's say I will go ahead and write for fruit for fruit in fruits. 481 00:22:43,000 --> 00:22:44,000 Right. 482 00:22:44,000 --> 00:22:48,000 And I will just go ahead and inside and print all the fruit items that I have. 483 00:22:49,000 --> 00:22:49,000 Right. 484 00:22:49,000 --> 00:22:53,000 So here one by one right now no fruit items is present or what. 485 00:22:53,000 --> 00:22:55,000 Okay, okay I have cleared that fruits. 486 00:22:55,000 --> 00:22:56,000 Right. 487 00:22:56,000 --> 00:22:57,000 So let me do one thing. 488 00:22:57,000 --> 00:23:02,000 Let me just take numbers over here so that I will be able to see through it. 489 00:23:02,000 --> 00:23:02,000 Right. 490 00:23:02,000 --> 00:23:05,000 For number in numbers. 491 00:23:05,000 --> 00:23:06,000 Right. 492 00:23:06,000 --> 00:23:08,000 So numbers is also a collection over here. 493 00:23:08,000 --> 00:23:10,000 List of collection list of elements. 494 00:23:10,000 --> 00:23:13,000 So 123456789 ten okay. 495 00:23:13,000 --> 00:23:14,000 So this is also there. 496 00:23:14,000 --> 00:23:18,000 Let's say I want to iterate all this list with indexes also. 497 00:23:19,000 --> 00:23:24,000 So I want to iterate iterating with index. 498 00:23:24,000 --> 00:23:31,000 So for this I can use for index, comma, fruit, fruit or index. 499 00:23:31,000 --> 00:23:34,000 Sorry for index comma number in numbers. 500 00:23:34,000 --> 00:23:37,000 Now once I use this numbers right. 501 00:23:37,000 --> 00:23:39,000 Obviously see if I'm directly using this numbers. 502 00:23:39,000 --> 00:23:42,000 I know this is a list, but if I want index information. 503 00:23:42,000 --> 00:23:46,000 Also I have an inbuilt function in Python which is called as enumerate okay. 504 00:23:46,000 --> 00:23:52,000 And if we specifically use this enumerate that basically means we are also going to get the index number. 505 00:23:52,000 --> 00:23:57,000 So if I go ahead and print index comma number, now you'll be able to see all the indexes. 506 00:23:57,000 --> 00:23:59,000 So this is my zeroth index. 507 00:23:59,000 --> 00:24:01,000 The first element is present in the zeroth index. 508 00:24:01,000 --> 00:24:06,000 Then I have two which is present in the first index then three in the second index, four in the third 509 00:24:06,000 --> 00:24:11,000 index, five in the fourth index, six in the fifth index, seven in the sixth index, eighth in the 510 00:24:11,000 --> 00:24:15,000 seventh index, nine in the eighth index, and ten in the ninth index. 511 00:24:15,000 --> 00:24:16,000 So I have all these things. 512 00:24:16,000 --> 00:24:20,000 And just by using this inbuilt function, you get an excess of the index number. 513 00:24:20,000 --> 00:24:24,000 Also along with the list of elements that are present in that particular list. 514 00:24:24,000 --> 00:24:30,000 Okay, so this is one amazing thing about uh, you know, you can also iterate over the list. 515 00:24:30,000 --> 00:24:32,000 You can also iterate along with the index. 516 00:24:32,000 --> 00:24:39,000 Right now let's go ahead and talk about one more amazing thing, which is basically called as list comprehension 517 00:24:39,000 --> 00:24:40,000 okay. 518 00:24:41,000 --> 00:24:43,000 Now list comprehension. 519 00:24:43,000 --> 00:24:47,000 Now guys, let's let's consider that, uh, I want to do something right. 520 00:24:47,000 --> 00:24:55,000 I want to probably, uh, let's say I'll write a for loop for x in range for x in range. 521 00:24:55,000 --> 00:24:57,000 Let's say I'm going to write ten. 522 00:24:58,000 --> 00:25:04,000 And here, uh, what I'm actually going to do is that I'm going to probably create a list element. 523 00:25:04,000 --> 00:25:07,000 Let's say I'm going to create a list empty elements. 524 00:25:07,000 --> 00:25:10,000 And then I will go ahead and write list dot append. 525 00:25:10,000 --> 00:25:13,000 And let me just go ahead and do this okay. 526 00:25:13,000 --> 00:25:15,000 So just imagine what I've actually done. 527 00:25:16,000 --> 00:25:21,000 Uh, here inside this for loop I'm squaring every number and I'm appending in this particular list. 528 00:25:21,000 --> 00:25:21,000 Right. 529 00:25:21,000 --> 00:25:25,000 And finally I can go ahead and print this particular list okay. 530 00:25:25,000 --> 00:25:30,000 So in short this is a code that I've actually written to square every numbers inside this particular 531 00:25:30,000 --> 00:25:31,000 range of numbers. 532 00:25:31,000 --> 00:25:32,000 Right. 533 00:25:32,000 --> 00:25:37,000 So I'm getting 01249 16, 25, 36, 49, 64, 81. 534 00:25:37,000 --> 00:25:39,000 Now see imagine in this line of code, right? 535 00:25:39,000 --> 00:25:41,000 I've written 3 to 4 lines right over here. 536 00:25:41,000 --> 00:25:43,000 I have, first of all, initialized an empty list. 537 00:25:43,000 --> 00:25:45,000 Then I'm putting a for loop. 538 00:25:45,000 --> 00:25:47,000 Then I'm performing this specific operation. 539 00:25:47,000 --> 00:25:51,000 What if I can perform this entire list operation? 540 00:25:51,000 --> 00:25:55,000 Because everything is happening inside a list itself, and we are creating a new list also over here, 541 00:25:55,000 --> 00:25:55,000 right? 542 00:25:55,000 --> 00:25:59,000 Obviously, if you're creating your list again, new list over here, again, playing with different 543 00:25:59,000 --> 00:26:01,000 different elements, more memory will be required. 544 00:26:01,000 --> 00:26:06,000 So Python actually helps us to play with list comprehension. 545 00:26:06,000 --> 00:26:14,000 Now in list comprehension it tells you that you can perform all this operation right within a list itself. 546 00:26:14,000 --> 00:26:14,000 Right. 547 00:26:14,000 --> 00:26:16,000 So now see this observe over here. 548 00:26:16,000 --> 00:26:23,000 Now I will go ahead and write for x in range ten. 549 00:26:23,000 --> 00:26:23,000 Right. 550 00:26:23,000 --> 00:26:27,000 So here if I go ahead and execute this uh okay. 551 00:26:27,000 --> 00:26:30,000 Right now it is giving me an error because it is invalid syntax I get it okay. 552 00:26:30,000 --> 00:26:32,000 Now let's let's do this okay. 553 00:26:32,000 --> 00:26:35,000 So first I have written for x in range of ten. 554 00:26:35,000 --> 00:26:37,000 So this is basically iterating through this. 555 00:26:37,000 --> 00:26:40,000 Now the next thing is that what kind of operation I'm performing. 556 00:26:40,000 --> 00:26:42,000 So I want to perform x square. 557 00:26:42,000 --> 00:26:45,000 So here if I go ahead and write x square. 558 00:26:45,000 --> 00:26:51,000 So list comprehension basically has two important things what we want as an output and what is the kind 559 00:26:51,000 --> 00:26:52,000 of operation that we are doing. 560 00:26:52,000 --> 00:26:52,000 Right. 561 00:26:52,000 --> 00:26:54,000 So see this is doing some kind of operation. 562 00:26:54,000 --> 00:26:56,000 So that needs to be displayed. 563 00:26:56,000 --> 00:26:57,000 And this is basically my iteration. 564 00:26:57,000 --> 00:26:59,000 So both of them are combined. 565 00:26:59,000 --> 00:27:03,000 If I go ahead and execute this you will be able to see that in a single list. 566 00:27:03,000 --> 00:27:05,000 I am able to get this specific answer. 567 00:27:05,000 --> 00:27:06,000 So here. 568 00:27:06,000 --> 00:27:06,000 What did I do? 569 00:27:06,000 --> 00:27:12,000 I did not have to create other list, item or list elements as such, right? 570 00:27:12,000 --> 00:27:17,000 All I did is that I probably, uh, you know, executed my code within a line of code. 571 00:27:17,000 --> 00:27:20,000 And what I really want is x square. 572 00:27:20,000 --> 00:27:22,000 I have written it in forward right now. 573 00:27:22,000 --> 00:27:25,000 Let's go ahead and see more examples with respect to list comprehension. 574 00:27:25,000 --> 00:27:27,000 So guys we have just seen one example. 575 00:27:27,000 --> 00:27:30,000 And I hope I know that you may be having some kind of confusion. 576 00:27:30,000 --> 00:27:37,000 So it is a better way that if I really want to make you understand about list comprehension, first 577 00:27:37,000 --> 00:27:43,000 of all, let's talk about a specific syntax like what kind of syntax we specifically use. 578 00:27:43,000 --> 00:27:43,000 Okay. 579 00:27:44,000 --> 00:27:46,000 Now uh, the basic syntax okay. 580 00:27:46,000 --> 00:27:49,000 Let me just make this as a markdown okay. 581 00:27:50,000 --> 00:27:51,000 Markdown over here okay. 582 00:27:51,000 --> 00:27:53,000 Let's comprehension. 583 00:27:53,000 --> 00:27:54,000 Okay. 584 00:27:54,000 --> 00:27:55,000 And this is important. 585 00:27:55,000 --> 00:27:58,000 So that is the reason I'm also going to show you the syntax over here. 586 00:27:58,000 --> 00:27:59,000 Okay. 587 00:27:59,000 --> 00:28:02,000 First of all the basic syntax okay. 588 00:28:03,000 --> 00:28:05,000 Now basic syntax is nothing. 589 00:28:05,000 --> 00:28:11,000 But it looks something like this expression for item in iterable. 590 00:28:11,000 --> 00:28:11,000 Right. 591 00:28:11,000 --> 00:28:16,000 So that is what we have done for item in iterable which is traversing everything. 592 00:28:16,000 --> 00:28:20,000 And this expression is going to perform on all the single items. 593 00:28:20,000 --> 00:28:20,000 Okay. 594 00:28:20,000 --> 00:28:22,000 This is the basic syntax okay. 595 00:28:23,000 --> 00:28:27,000 Now I may also have other option like with conditional logic okay. 596 00:28:27,000 --> 00:28:29,000 If I want to apply some logic over here. 597 00:28:29,000 --> 00:28:33,000 So with conditional logic the expression looks a little bit different. 598 00:28:33,000 --> 00:28:34,000 Okay. 599 00:28:34,000 --> 00:28:36,000 And let me just show you this particular expression also. 600 00:28:36,000 --> 00:28:37,000 Okay. 601 00:28:37,000 --> 00:28:41,000 So here you can see expression for item in iterable if condition. 602 00:28:41,000 --> 00:28:42,000 Also I can put. 603 00:28:42,000 --> 00:28:44,000 So I'm putting if condition over here. 604 00:28:44,000 --> 00:28:46,000 So any kind of conditional logic is there. 605 00:28:46,000 --> 00:28:52,000 You have to probably put it at the last iterate whatever iteration you really want to do, you want 606 00:28:52,000 --> 00:28:55,000 to put in the center and any kind of expression that you want to perform. 607 00:28:55,000 --> 00:28:56,000 You can put it in the starting. 608 00:28:56,000 --> 00:28:57,000 Okay. 609 00:28:57,000 --> 00:29:01,000 Now based on this we will try to see some kind of example. 610 00:29:01,000 --> 00:29:01,000 Okay. 611 00:29:01,000 --> 00:29:05,000 So but remember this this is super super important okay. 612 00:29:05,000 --> 00:29:07,000 And you have to use with respect to this itself. 613 00:29:07,000 --> 00:29:08,000 Right. 614 00:29:08,000 --> 00:29:11,000 So let's consider one example. 615 00:29:11,000 --> 00:29:15,000 So let me go ahead and write basic list comprehension. 616 00:29:18,000 --> 00:29:18,000 Okay. 617 00:29:18,000 --> 00:29:23,000 Let's say I want to do a square off all the number okay. 618 00:29:23,000 --> 00:29:26,000 Square off all the number okay. 619 00:29:26,000 --> 00:29:28,000 Square off a set of numbers. 620 00:29:28,000 --> 00:29:35,000 So I will write for x or for num in range of ten. 621 00:29:35,000 --> 00:29:36,000 Right. 622 00:29:36,000 --> 00:29:40,000 And for every of this number I just need to do num square. 623 00:29:42,000 --> 00:29:42,000 Right. 624 00:29:42,000 --> 00:29:43,000 Square. 625 00:29:46,000 --> 00:29:46,000 Done. 626 00:29:46,000 --> 00:29:52,000 Now if I go ahead and print this in short what I'm actually going to get, I'm going to basically get 627 00:29:52,000 --> 00:29:53,000 the square of this number. 628 00:29:53,000 --> 00:29:57,000 Now what condition I have applied over here basic syntax for item in iterable. 629 00:29:57,000 --> 00:29:59,000 And then I have expression okay. 630 00:29:59,000 --> 00:30:01,000 Now coming to the next one okay. 631 00:30:01,000 --> 00:30:08,000 Let's say let's consider with list comprehension with condition okay a specific condition over here 632 00:30:08,000 --> 00:30:08,000 okay. 633 00:30:08,000 --> 00:30:14,000 And let's say I will try to find out from a list of elements which are which are basically even numbers. 634 00:30:14,000 --> 00:30:15,000 Okay, okay. 635 00:30:15,000 --> 00:30:17,000 Which are even numbers. 636 00:30:17,000 --> 00:30:23,000 Now, let's say if I go ahead and write in for loop for I in range ten, okay. 637 00:30:24,000 --> 00:30:32,000 If I go ahead and write, if I colon two is double equal to zero, right, then what I have to do print. 638 00:30:32,000 --> 00:30:36,000 Or I will probably create a list and I'll append all the even elements. 639 00:30:36,000 --> 00:30:37,000 Right. 640 00:30:37,000 --> 00:30:40,000 So let's say I have created a list an empty list over here. 641 00:30:40,000 --> 00:30:47,000 And now what I'm actually going to do I'm going to basically write list dot append list dot append. 642 00:30:48,000 --> 00:30:51,000 And here I'm going to basically write my I right. 643 00:30:51,000 --> 00:30:58,000 So finally if I go ahead and print my list, you'll be able to see that all the even elements will come 644 00:30:58,000 --> 00:31:00,000 right till this particular ten number. 645 00:31:00,000 --> 00:31:00,000 Right. 646 00:31:01,000 --> 00:31:06,000 But here you need to see how do I convert this into list comprehension. 647 00:31:06,000 --> 00:31:10,000 And I showed you one expression with conditional logic. 648 00:31:10,000 --> 00:31:12,000 Expression is over here for item in iterable is here. 649 00:31:12,000 --> 00:31:17,000 And if condition is over here now the same thing I will try to convert this into list comprehension. 650 00:31:17,000 --> 00:31:22,000 So I will write for I or for num in range. 651 00:31:22,000 --> 00:31:28,000 Range 20 okay or ten okay I have to display the number itself. 652 00:31:28,000 --> 00:31:29,000 So I will right number. 653 00:31:29,000 --> 00:31:31,000 I don't need to even apply any expression. 654 00:31:31,000 --> 00:31:34,000 But here I will go ahead and write one if condition. 655 00:31:34,000 --> 00:31:40,000 I will say hey if num percentile two or modulus two is double equal to zero. 656 00:31:40,000 --> 00:31:45,000 Now this basically becomes my event underscore numbers. 657 00:31:45,000 --> 00:31:48,000 Right now here I do not have to even create a new list. 658 00:31:48,000 --> 00:31:49,000 Right. 659 00:31:49,000 --> 00:31:51,000 All I'm doing it in one single line of code. 660 00:31:51,000 --> 00:31:54,000 So this way my execution will happen quicker, right? 661 00:31:54,000 --> 00:31:55,000 It will be faster. 662 00:31:56,000 --> 00:31:59,000 So I hope you are getting this as an idea. 663 00:31:59,000 --> 00:31:59,000 Okay. 664 00:31:59,000 --> 00:32:01,000 Now one more. 665 00:32:01,000 --> 00:32:02,000 One more thing, is there? 666 00:32:02,000 --> 00:32:02,000 Okay. 667 00:32:02,000 --> 00:32:07,000 One more, very important, uh, thing is there, which is again a type of list comprehension you can 668 00:32:07,000 --> 00:32:11,000 basically say which is called as nested list comprehension. 669 00:32:11,000 --> 00:32:13,000 So let me just go ahead and write it down. 670 00:32:13,000 --> 00:32:22,000 So here you have something called as a nested list comprehension okay. 671 00:32:22,000 --> 00:32:23,000 And it is good to know all these things. 672 00:32:23,000 --> 00:32:28,000 Guys I am trying my level best so that you will be able to understand multiple things. 673 00:32:28,000 --> 00:32:28,000 Okay. 674 00:32:29,000 --> 00:32:35,000 So here you can see and here you can see now what is so different when compared to this okay. 675 00:32:36,000 --> 00:32:40,000 Now here we are iterating through two different iterables. 676 00:32:40,000 --> 00:32:47,000 So for item in iterable one for item two in iterable two, then we are writing an expression. 677 00:32:47,000 --> 00:32:49,000 So that basically means if I have two lists. 678 00:32:49,000 --> 00:32:54,000 And then on top of that two list I want to perform any kind of list comprehension. 679 00:32:54,000 --> 00:32:56,000 Then I can use this nested list comprehension. 680 00:32:56,000 --> 00:32:59,000 So let me show you one perfect example. 681 00:32:59,000 --> 00:32:59,000 Okay. 682 00:32:59,000 --> 00:33:05,000 Let me just go ahead and write it over here and let me write it as nested list. 683 00:33:07,000 --> 00:33:09,000 Comprehension. 684 00:33:09,000 --> 00:33:10,000 Okay. 685 00:33:11,000 --> 00:33:12,000 Comprehension. 686 00:33:14,000 --> 00:33:17,000 So let me go ahead and create my list one. 687 00:33:17,000 --> 00:33:20,000 And this will be 123 okay. 688 00:33:20,000 --> 00:33:29,000 Or I'll take one more element for let me say this is my list two which will be nothing but a. 689 00:33:30,000 --> 00:33:36,000 b, C, d. 690 00:33:36,000 --> 00:33:38,000 Okay, so these are my four elements. 691 00:33:38,000 --> 00:33:40,000 Now let me do one very simple thing. 692 00:33:40,000 --> 00:33:47,000 Okay I will try to make a pair pairs of list one and list two elements okay. 693 00:33:47,000 --> 00:33:51,000 So first of all I will iterate through list one. 694 00:33:51,000 --> 00:33:55,000 So let me just go ahead and write for I in list one okay. 695 00:33:55,000 --> 00:33:59,000 Then I will iterate through list two for j in list two okay. 696 00:33:59,000 --> 00:34:02,000 And then I have to pair it right. 697 00:34:02,000 --> 00:34:07,000 Now for pairing I will be using a tuple I have not discussed yet about a tuple, but I'm just going 698 00:34:07,000 --> 00:34:09,000 to take this I and j and pair it together. 699 00:34:09,000 --> 00:34:11,000 Okay, just write it in this way. 700 00:34:11,000 --> 00:34:13,000 Okay, now you can see. 701 00:34:13,000 --> 00:34:18,000 Or if you don't want to like write like this you can also use list over here Okay, let's see whether 702 00:34:18,000 --> 00:34:19,000 this will work or not. 703 00:34:19,000 --> 00:34:25,000 And now I'm just going to print pair okay. 704 00:34:25,000 --> 00:34:31,000 Appear appear have written pair okay so here you can see one comma one comma b one comma c one comma 705 00:34:31,000 --> 00:34:34,000 d two comma two comma b two comma c two comma d. 706 00:34:34,000 --> 00:34:40,000 So it is just doing all the pairing 1A1B1C1D2A2B2C2D. 707 00:34:40,000 --> 00:34:41,000 So this is what is happening. 708 00:34:41,000 --> 00:34:44,000 First of all this will iterate right with respect to one element. 709 00:34:44,000 --> 00:34:46,000 Then it will iterate all the elements right. 710 00:34:46,000 --> 00:34:49,000 We can also write this in this particular way also. 711 00:34:49,000 --> 00:34:50,000 Right. 712 00:34:50,000 --> 00:34:53,000 But again lot of lines of code we really need to write. 713 00:34:53,000 --> 00:34:55,000 But this is really really powerful. 714 00:34:55,000 --> 00:34:59,000 And here you can actually see with the help of nested list comprehension we are able to do it right 715 00:34:59,000 --> 00:35:01,000 now in Python. 716 00:35:01,000 --> 00:35:04,000 Also you have lot of inbuilt key functions right. 717 00:35:04,000 --> 00:35:07,000 So we can actually use list comprehension. 718 00:35:08,000 --> 00:35:11,000 List comprehension. 719 00:35:11,000 --> 00:35:15,000 With function calls you can create your own custom function and all. 720 00:35:15,000 --> 00:35:21,000 But right now I'm going to show you some uh inbuilt functions okay. 721 00:35:21,000 --> 00:35:23,000 So inbuilt function will try to see. 722 00:35:23,000 --> 00:35:28,000 So list comprehension with this let's say and I will I will show you the code over here. 723 00:35:28,000 --> 00:35:32,000 So here I have words like hello world, Python list comprehension. 724 00:35:32,000 --> 00:35:34,000 Now see everybody focus. 725 00:35:34,000 --> 00:35:37,000 So I'm writing for words in words and I'm just saying length of word. 726 00:35:37,000 --> 00:35:37,000 Right. 727 00:35:37,000 --> 00:35:40,000 So it is just going to give us the length of word over here. 728 00:35:40,000 --> 00:35:41,000 Right. 729 00:35:41,000 --> 00:35:44,000 And how easily we are able to see this particular output. 730 00:35:44,000 --> 00:35:44,000 Right. 731 00:35:44,000 --> 00:35:46,000 And this looks amazing. 732 00:35:46,000 --> 00:35:47,000 Right. 733 00:35:47,000 --> 00:35:51,000 And most of the things are basically very much simple over here right now. 734 00:35:51,000 --> 00:35:58,000 Uh, there is also one more list comprehension technique where you can use else block also. 735 00:35:58,000 --> 00:36:01,000 So, uh, I will give you that as an assignment. 736 00:36:01,000 --> 00:36:02,000 Please make sure that you do it. 737 00:36:02,000 --> 00:36:07,000 But don't worry as we go ahead and run, learn more about the tuples and all there. 738 00:36:07,000 --> 00:36:12,000 Also, we'll be covering more about it, but I hope, uh, you got an idea with respect to list comprehension. 739 00:36:12,000 --> 00:36:17,000 And uh, this was all about the discussion with respect to list. 740 00:36:17,000 --> 00:36:21,000 And, uh, I think I tried my level best to cover almost each and every thing. 741 00:36:21,000 --> 00:36:22,000 Okay. 742 00:36:22,000 --> 00:36:26,000 And at the end of the day, you really need to try more and more to understand more. 743 00:36:26,000 --> 00:36:28,000 Example, unless you don't practice. 744 00:36:28,000 --> 00:36:29,000 Uh, I don't think so. 745 00:36:29,000 --> 00:36:33,000 You will be able to do any perfection in this. 746 00:36:33,000 --> 00:36:33,000 Right. 747 00:36:33,000 --> 00:36:35,000 So more examples, more things. 748 00:36:35,000 --> 00:36:39,000 But at the end of the day, I would like to give the conclusion of this lesson and probably talk about 749 00:36:39,000 --> 00:36:42,000 it, you know, because list is something really important. 750 00:36:42,000 --> 00:36:43,000 So the list. 751 00:36:44,000 --> 00:36:48,000 So here you can see I have given some conclusion with respect to the list comprehension, a powerful 752 00:36:48,000 --> 00:36:50,000 and concise to create list in Python. 753 00:36:50,000 --> 00:36:56,000 They are syntactically syntactically compact and can replace more verbose looping construct. 754 00:36:56,000 --> 00:37:01,000 Understand the syntax of list comprehension will help you write cleaner and more efficient Python code, 755 00:37:01,000 --> 00:37:01,000 right? 756 00:37:01,000 --> 00:37:03,000 So yes, uh, this was it. 757 00:37:03,000 --> 00:37:07,000 Uh, I will see you all in the next video where we will be talking about the next data structure. 758 00:37:07,000 --> 00:37:07,000 Thank.