1 00:00:00,630 --> 00:00:02,350 Hello there and welcome. 2 00:00:02,380 --> 00:00:07,340 See sharp list what is a list in C sharp. 3 00:00:07,440 --> 00:00:18,930 A list is an object which holds variables in a specific order lists are like arrays. 4 00:00:18,930 --> 00:00:30,820 But one main difference between a list and an array is that with a list they are dynamically sized. 5 00:00:30,890 --> 00:00:40,010 That means you don't necessarily have to know what is going to be in the list so you can not die dynamically 6 00:00:40,340 --> 00:00:43,870 added on or their size as it goes on. 7 00:00:44,690 --> 00:00:48,330 While an array has a fixed size. 8 00:00:48,350 --> 00:00:55,840 So if you want to use an array you know beforehand what the array will contain. 9 00:00:55,920 --> 00:01:05,270 But if you're not sure what the amount of variables will be is best to use a list because a dynamically 10 00:01:05,600 --> 00:01:07,580 sized. 11 00:01:08,210 --> 00:01:12,950 The basic syntax for right in the list is this. 12 00:01:13,040 --> 00:01:17,750 So you start with a name list followed by the data type. 13 00:01:17,870 --> 00:01:29,090 In this example here we are defining a list called numbers which will hold integers integers are numbers 14 00:01:31,260 --> 00:01:39,440 once the list has been initialized we can insert numbers into the list. 15 00:01:39,790 --> 00:01:48,890 I have got visual studio opened and I've just commented out some call I wrote in in the lecture for 16 00:01:48,960 --> 00:01:49,650 a raise. 17 00:01:49,650 --> 00:02:01,410 I'm just going to use the same the same program here to keep an example of how to set up a list. 18 00:02:01,530 --> 00:02:12,150 So we're going to start by initializing the list to type in list followed by the data type which would 19 00:02:12,150 --> 00:02:13,170 be an integer 20 00:02:15,840 --> 00:02:17,630 followed by the name. 21 00:02:17,660 --> 00:02:24,920 I want to keep the list I in numbers and to create a new instance of it. 22 00:02:25,150 --> 00:02:41,380 You do the equals to new list and path in the data type and then a semicolon at the end. 23 00:02:41,840 --> 00:02:42,350 So 24 00:02:44,930 --> 00:02:51,080 before the semicolon you need to put parentheses open on closing period. 25 00:02:51,090 --> 00:02:52,110 This is OK. 26 00:02:53,720 --> 00:03:02,890 So now that the list has been initialized I can append or add to the list to add to the list. 27 00:03:02,900 --> 00:03:06,620 All I need is the name of the list which is numbers 28 00:03:10,130 --> 00:03:21,180 followed followed by a dot and then the word add add is a method a built in method and a parent who 29 00:03:21,200 --> 00:03:28,810 sees are passing the number I want to add Okay so I've now added. 30 00:03:28,980 --> 00:03:32,600 And number one I can do the same. 31 00:03:32,820 --> 00:03:40,800 Just copy it a few times just to save time and come here again. 32 00:03:44,650 --> 00:03:49,720 Now just change the numbers or this change to 2. 33 00:03:50,280 --> 00:03:57,380 These are changed to 3 and these are changed to 4 34 00:04:01,620 --> 00:04:08,800 so we can display the count of the of what's in the list. 35 00:04:08,970 --> 00:04:13,530 Using a console log so we can display it on the console so you typing console 36 00:04:17,060 --> 00:04:31,790 console dot right line and in the right line you pass in the name of the list. 37 00:04:32,690 --> 00:04:35,240 Numbers don't count. 38 00:04:35,800 --> 00:04:43,680 So we use the count to count the count as a built in function. 39 00:04:43,690 --> 00:04:54,200 So we need to use the count to count the numbers in the list and we're going to attach a console the 40 00:04:54,220 --> 00:04:56,380 read line to that as well. 41 00:04:56,680 --> 00:05:04,960 Because if we don't use a console the red line we will not see see displayed on the screen long enough 42 00:05:08,760 --> 00:05:10,250 without using the console. 43 00:05:10,250 --> 00:05:11,580 The red line. 44 00:05:11,580 --> 00:05:15,210 It will just execute quickly and exit the screen. 45 00:05:15,210 --> 00:05:23,220 But with you if you are the console the red line it executes and displays the result on the screen. 46 00:05:23,220 --> 00:05:26,610 So we know we've got four items in the list. 47 00:05:26,640 --> 00:05:29,130 So I expect the count to show four. 48 00:05:29,610 --> 00:05:34,270 So click on Start to debug it. 49 00:05:35,310 --> 00:05:38,950 As you can see it is showing for. 50 00:05:39,030 --> 00:05:45,030 So the same way you add to a list. 51 00:05:45,090 --> 00:05:49,380 You can also remove from a list. 52 00:05:49,380 --> 00:05:57,420 So if I wanted to remove from the list all I had to do was just come down here. 53 00:05:57,420 --> 00:05:58,140 I type here. 54 00:05:58,170 --> 00:06:06,210 I'll start with the name of the variable with which is the the list name list names called numbers. 55 00:06:06,210 --> 00:06:07,830 So I type in numbers 56 00:06:10,110 --> 00:06:12,870 dot remove. 57 00:06:12,870 --> 00:06:15,110 Notice the removed method here. 58 00:06:15,540 --> 00:06:20,130 And then in that are passing the value I want to remove. 59 00:06:20,140 --> 00:06:22,410 So I want to remove for 60 00:06:25,380 --> 00:06:26,580 okay. 61 00:06:26,810 --> 00:06:36,680 If I now execute this statement I expect the list to only display a count of three. 62 00:06:36,680 --> 00:06:43,790 So let me run that so that we can see as you can see is displayed a count of three. 63 00:06:46,100 --> 00:06:49,250 So we've done an example using an integer. 64 00:06:49,640 --> 00:06:58,520 So I'm gonna do an example now using a string is basically the same thing you just substitute the integer 65 00:06:58,880 --> 00:07:00,350 with a string. 66 00:07:00,470 --> 00:07:02,820 So you just I'm just gonna. 67 00:07:02,950 --> 00:07:07,120 Quickly to save time and then I'll explain it to you but it's basically the same. 68 00:07:08,380 --> 00:07:13,980 Okay so I defined another list here this time a string. 69 00:07:14,120 --> 00:07:18,310 So we've already have already showed you an example with an integer. 70 00:07:18,350 --> 00:07:20,970 So this is an example with a string. 71 00:07:21,300 --> 00:07:27,830 I've created a list the data type is a string I've given it the name of fruits created a new instance 72 00:07:27,830 --> 00:07:35,740 here called list and use the add method here to add to the list. 73 00:07:35,870 --> 00:07:43,120 So I've added this for items to the list and I've got to console the right line here with a count. 74 00:07:43,520 --> 00:07:50,350 So this count will enable me to count what we have in the list to is should display for items. 75 00:07:50,350 --> 00:07:59,480 So let me run that click on Start and it should display form so she can see they've got four displayed. 76 00:07:59,480 --> 00:08:00,200 All right. 77 00:08:00,200 --> 00:08:08,400 So you can experiment and try and create various list your self notice that with the string data type 78 00:08:08,400 --> 00:08:16,260 you have to enclose the values in quotes because they ha text does you know where B computer can understand 79 00:08:16,260 --> 00:08:17,460 them. 80 00:08:17,820 --> 00:08:20,910 So that's set for this lecture on list. 81 00:08:20,910 --> 00:08:22,080 Thanks for watching. 82 00:08:22,080 --> 00:08:22,680 Bye for now.