f1c9b08cf3
This includes certificates (where it does nothing), but does not include any translations.
82 lines
2.1 KiB
Markdown
82 lines
2.1 KiB
Markdown
---
|
|
id: 56bbb991ad1ed5201cd392ca
|
|
title: Access Array Data with Indexes
|
|
challengeType: 1
|
|
isHidden: false
|
|
videoUrl: 'https://scrimba.com/c/cBZQbTz'
|
|
forumTopicId: 16158
|
|
---
|
|
|
|
## Description
|
|
<section id='description'>
|
|
We can access the data inside arrays using <dfn>indexes</dfn>.
|
|
Array indexes are written in the same bracket notation that strings use, except that instead of specifying a character, they are specifying an entry in the array. Like strings, arrays use <dfn>zero-based</dfn> indexing, so the first element in an array has an index of <code>0</code>.
|
|
<br />
|
|
<strong>Example</strong>
|
|
|
|
```js
|
|
var array = [50,60,70];
|
|
array[0]; // equals 50
|
|
var data = array[1]; // equals 60
|
|
```
|
|
|
|
<strong>Note</strong><br>There shouldn't be any spaces between the array name and the square brackets, like <code>array [0]</code>. Although JavaScript is able to process this correctly, this may confuse other programmers reading your code.
|
|
</section>
|
|
|
|
## Instructions
|
|
<section id='instructions'>
|
|
Create a variable called <code>myData</code> and set it to equal the first value of <code>myArray</code> using bracket notation.
|
|
</section>
|
|
|
|
## Tests
|
|
<section id='tests'>
|
|
|
|
```yml
|
|
tests:
|
|
- text: The variable <code>myData</code> should equal the first value of <code>myArray</code>.
|
|
testString: assert((function(){if(typeof myArray !== 'undefined' && typeof myData !== 'undefined' && myArray[0] === myData){return true;}else{return false;}})());
|
|
- text: The data in variable <code>myArray</code> should be accessed using bracket notation.
|
|
testString: assert((function(){if(code.match(/\s*=\s*myArray\[0\]/g)){return true;}else{return false;}})());
|
|
|
|
```
|
|
|
|
</section>
|
|
|
|
## Challenge Seed
|
|
<section id='challengeSeed'>
|
|
|
|
<div id='js-seed'>
|
|
|
|
```js
|
|
// Setup
|
|
var myArray = [50,60,70];
|
|
|
|
// Only change code below this line
|
|
|
|
```
|
|
|
|
</div>
|
|
|
|
|
|
### After Test
|
|
<div id='js-teardown'>
|
|
|
|
```js
|
|
if(typeof myArray !== "undefined" && typeof myData !== "undefined"){(function(y,z){return 'myArray = ' + JSON.stringify(y) + ', myData = ' + JSON.stringify(z);})(myArray, myData);}
|
|
```
|
|
|
|
</div>
|
|
|
|
</section>
|
|
|
|
## Solution
|
|
<section id='solution'>
|
|
|
|
|
|
```js
|
|
var myArray = [50,60,70];
|
|
var myData = myArray[0];
|
|
```
|
|
|
|
</section>
|