1 00:00:00,550 --> 00:00:05,980 This section is all about JavaScript arrays. 2 00:00:06,250 --> 00:00:13,100 This section will contain a lot of coding, challenge any concepts that you learn. 3 00:00:13,120 --> 00:00:16,120 You're going to have a coding challenge about it. 4 00:00:16,850 --> 00:00:22,730 And also the PDF Guide, the script and the final code will be provided. 5 00:00:22,730 --> 00:00:26,090 So make sure we download so that we can follow along. 6 00:00:26,360 --> 00:00:30,740 Well, the next question is what is an array? 7 00:00:31,340 --> 00:00:40,430 Well, arrays are collection of items in a particular order and can be accessed by the index number. 8 00:00:41,030 --> 00:00:49,430 Well, until this point, you know how we are storing or saving data that is using the data types like 9 00:00:49,430 --> 00:00:50,480 variables. 10 00:00:50,480 --> 00:00:56,390 We can store data into variables or string number or boolean. 11 00:00:56,540 --> 00:01:01,970 So arrays is going to take that kind of data storage in the next level. 12 00:01:02,120 --> 00:01:05,209 So as you could see here, this works. 13 00:01:05,209 --> 00:01:08,300 We are going to talk about how to create an array. 14 00:01:08,480 --> 00:01:16,610 It we see that the first option here we can save a couple of items in one single variable. 15 00:01:16,940 --> 00:01:19,670 The same thing applies to the line number three. 16 00:01:19,700 --> 00:01:29,540 Here we are saving this record into one variable, meaning that one variable can contains a lot of data 17 00:01:29,570 --> 00:01:34,460 on unlike the strings and the numbers that are types for arrays. 18 00:01:34,490 --> 00:01:38,510 We can save multiple collection of record. 19 00:01:38,780 --> 00:01:44,210 So let's do a few more to use this diagram to explain what is array. 20 00:01:44,570 --> 00:01:53,420 One good thing we need to bear in mind is that arrays are index based, meaning that the index determine 21 00:01:53,420 --> 00:01:58,280 where this particular record or data is located. 22 00:01:58,460 --> 00:02:05,150 So we have index zero one and two, meaning when we say arrays are index based, meaning that they start 23 00:02:05,150 --> 00:02:06,020 from zero. 24 00:02:06,200 --> 00:02:12,980 So if we want to count, if we want to get the first record that won't reference as index zero, we 25 00:02:12,980 --> 00:02:18,140 would w more to create an access search record for the mean time. 26 00:02:18,170 --> 00:02:19,730 Let's explore more. 27 00:02:20,030 --> 00:02:20,600 All right. 28 00:02:20,600 --> 00:02:28,100 So let's say that for our purpose, we are going to create a race of books, meaning that we have a 29 00:02:28,100 --> 00:02:30,170 list of books that we want to save. 30 00:02:30,750 --> 00:02:32,290 Okay, let's say we have five books. 31 00:02:32,300 --> 00:02:33,550 Let's say we have one book. 32 00:02:33,560 --> 00:02:38,060 For example, we're thinking that, well, then that one's pretty easy. 33 00:02:38,060 --> 00:02:41,270 I can just declare a variable, say const. 34 00:02:42,090 --> 00:02:42,810 Let's say. 35 00:02:44,760 --> 00:02:50,010 And then is equal to, let's say the book name is called Kiss. 36 00:02:50,640 --> 00:02:51,420 Then I'm done. 37 00:02:51,420 --> 00:02:52,930 So why do I need a red? 38 00:02:53,400 --> 00:02:54,900 Okay for one book? 39 00:02:55,110 --> 00:02:56,040 It's okay. 40 00:02:56,070 --> 00:02:56,640 Whatever. 41 00:02:56,640 --> 00:02:57,990 If you have two books. 42 00:02:58,350 --> 00:02:59,590 All right, let's see now. 43 00:02:59,610 --> 00:03:00,010 Okay. 44 00:03:00,030 --> 00:03:01,210 It's also easy. 45 00:03:01,230 --> 00:03:03,990 I can also declare a variable called cost. 46 00:03:04,260 --> 00:03:10,410 And I will say book two is equal to Node.js. 47 00:03:11,980 --> 00:03:12,400 Yeah. 48 00:03:12,460 --> 00:03:13,610 It's also easy, right? 49 00:03:13,680 --> 00:03:14,830 Okay, that's perfect. 50 00:03:14,860 --> 00:03:20,020 What about if we have 100 books? 51 00:03:20,290 --> 00:03:22,450 Are you going to create a variable for book one? 52 00:03:22,450 --> 00:03:24,380 Book two, book three and like that? 53 00:03:24,400 --> 00:03:24,990 No. 54 00:03:25,000 --> 00:03:27,910 That is why a race comes into play. 55 00:03:29,170 --> 00:03:29,440 Okay. 56 00:03:29,440 --> 00:03:37,600 So let's take it that in one case we are going to create an array of books and we have taken this shelf 57 00:03:37,600 --> 00:03:39,820 that's going to hold our book. 58 00:03:39,840 --> 00:03:47,710 So this one is an array, array box, contain lines in the hallway and now it's ready to have some books 59 00:03:47,710 --> 00:03:51,400 in it and can see that we have individual shelves here. 60 00:03:51,400 --> 00:03:54,340 So these are the indexes in my array. 61 00:03:54,490 --> 00:04:02,740 So let's see that for the first sheriff, I have book one and it's going to donate zero index to it, 62 00:04:03,070 --> 00:04:10,900 meaning that if I want to retrieve this book, I need to reference zero in the zero, meaning it represents 63 00:04:10,900 --> 00:04:11,470 this book. 64 00:04:11,470 --> 00:04:15,760 Then I can take some book out if I reference index zero. 65 00:04:16,209 --> 00:04:18,670 What about if I want to put another book here? 66 00:04:18,670 --> 00:04:22,420 Then the same thing is going to give me as index one. 67 00:04:22,450 --> 00:04:25,750 The next book as that index too. 68 00:04:25,750 --> 00:04:29,410 And the last book here, give me as index three. 69 00:04:29,650 --> 00:04:40,690 So these indexes you see here is being created for us automatically as soon as we create an array instance. 70 00:04:40,690 --> 00:04:43,030 Here, let me show you here what we have here. 71 00:04:43,030 --> 00:04:43,780 Yes. 72 00:04:43,990 --> 00:04:49,870 As soon as you make this square bracket here, it means that we are creating an array or using this 73 00:04:49,870 --> 00:04:50,590 syntax. 74 00:04:50,980 --> 00:04:51,250 Good. 75 00:04:51,310 --> 00:04:57,730 So in this video, let's see how we can create array from scratch using code.