JavaScript Array Overview

[MUSIC] 0:00 Arrays are one of the most useful data types you have as a JavaScript developer. 0:04 Arrays are the best way to group similar data together in a sequence, 0:10 such as a list of customers, photos, dates, or 0:14 even coordinates indicating a precise spot on a screen. 0:18 To use arrays effectively, 0:22 you need a way of looking through them to see the data they hold. 0:23 This action of looking through arrays is called iteration, and 0:27 JavaScript provides many methods for iterating over an array. 0:31 For example, you might wanna transform an array's elements, say, 0:35 from strings to numbers. 0:39 Or you might want to add an array of numbers and return the sum. 0:41 Maybe you have an array of dates and 0:45 you want to remove all dates before, say, July 1st. 0:47 In this course, 0:51 I'll show you how to use array methods to accomplish these kinds of tasks. 0:52 You'll also practice iterating over arrays so 0:57 you can retain the knowledge you'll build here. 0:59 Before diving in though, let's take a moment to review what arrays are. 1:03 An array is a sequenced selection of data, basically a list of information. 1:08 In fact, arrays are sometimes referred to as list like objects in JavaScript. 1:13 Think of a list on a piece of paper, like a shopping list for example. 1:19 A shopping list is a group of items you need to buy. 1:23 Those items appear in specific order, starting at the top and going down. 1:27 So when you want to add something to the list, you write it at the bottom. 1:32 JavaScript arrays have similar characteristics. 1:37 You can store and position data inside them as you can with a list. 1:40 To add data to an array, you typically write it in using a push method for 1:44 example. 1:49 Storing anything whether it is a name on a list or 1:51 an item in an array is useless unless you can find it again later. 1:54 To find a list item, you'll typically start reading at the top and 1:58 go down till you see what you're after. 2:02 You can look through arrays in a similar manner, but with arrays, 2:05 this process is called iteration. 2:09 And unlike a shopping list, 2:11 which is really a collection of strings, the names of each item you want to buy, 2:13 you can store any JavaScript data type as an item in an array. 2:18 A string, a number, an object, and even another array. 2:22 JavaScript uses integers called indices to identify the position 2:27 of an item in an array. 2:31 The first item in an array is that index 0, the next item is at 1 and so on. 2:33 This means if you know the location of an item in an array, 2:40 you can access it directly with its index. 2:43 Put the index and 2:46 square brackets after the array to access a specific piece of data. 2:47 In the next video, we'll compare two way to iterate over an array. 2:52 A for loop, and an array method called for each, I'll see you there. 2:57