* feat(curriculum): Add Basic JS Scrimba links * Fix: Add missing video url. * fix: update videoUrl
81 lines
2.5 KiB
Markdown
81 lines
2.5 KiB
Markdown
---
|
|
id: 56bbb991ad1ed5201cd392cc
|
|
title: Manipulate Arrays With pop()
|
|
challengeType: 1
|
|
videoUrl: 'https://scrimba.com/c/cRbVZAB'
|
|
---
|
|
|
|
## Description
|
|
<section id='description'>
|
|
Another way to change the data in an array is with the <code>.pop()</code> function.
|
|
<code>.pop()</code> is used to "pop" a value off of the end of an array. We can store this "popped off" value by assigning it to a variable. In other words, <code>.pop()</code> removes the last element from an array and returns that element.
|
|
Any type of entry can be "popped" off of an array - numbers, strings, even nested arrays.
|
|
<blockquote><code>var threeArr = [1, 4, 6];<br> var oneDown = threeArr.pop();<br> console.log(oneDown); // Returns 6<br> console.log(threeArr); // Returns [1, 4]</code></blockquote>
|
|
</section>
|
|
|
|
## Instructions
|
|
<section id='instructions'>
|
|
Use the <code>.pop()</code> function to remove the last item from <code>myArray</code>, assigning the "popped off" value to <code>removedFromMyArray</code>.
|
|
</section>
|
|
|
|
## Tests
|
|
<section id='tests'>
|
|
|
|
```yml
|
|
tests:
|
|
- text: <code>myArray</code> should only contain <code>[["John", 23]]</code>.
|
|
testString: assert((function(d){if(d[0][0] == 'John' && d[0][1] === 23 && d[1] == undefined){return true;}else{return false;}})(myArray), '<code>myArray</code> should only contain <code>[["John", 23]]</code>.');
|
|
- text: Use <code>pop()</code> on <code>myArray</code>
|
|
testString: assert(/removedFromMyArray\s*=\s*myArray\s*.\s*pop\s*(\s*)/.test(code), 'Use <code>pop()</code> on <code>myArray</code>');
|
|
- text: <code>removedFromMyArray</code> should only contain <code>["cat", 2]</code>.
|
|
testString: assert((function(d){if(d[0] == 'cat' && d[1] === 2 && d[2] == undefined){return true;}else{return false;}})(removedFromMyArray), '<code>removedFromMyArray</code> should only contain <code>["cat", 2]</code>.');
|
|
|
|
```
|
|
|
|
</section>
|
|
|
|
## Challenge Seed
|
|
<section id='challengeSeed'>
|
|
|
|
<div id='js-seed'>
|
|
|
|
```js
|
|
// Example
|
|
var ourArray = [1,2,3];
|
|
var removedFromOurArray = ourArray.pop();
|
|
// removedFromOurArray now equals 3, and ourArray now equals [1,2]
|
|
|
|
// Setup
|
|
var myArray = [["John", 23], ["cat", 2]];
|
|
|
|
// Only change code below this line.
|
|
var removedFromMyArray;
|
|
|
|
|
|
```
|
|
|
|
</div>
|
|
|
|
|
|
### After Test
|
|
<div id='js-teardown'>
|
|
|
|
```js
|
|
(function(y, z){return 'myArray = ' + JSON.stringify(y) + ' & removedFromMyArray = ' + JSON.stringify(z);})(myArray, removedFromMyArray);
|
|
```
|
|
|
|
</div>
|
|
|
|
</section>
|
|
|
|
## Solution
|
|
<section id='solution'>
|
|
|
|
|
|
```js
|
|
var myArray = [["John", 23], ["cat", 2]];
|
|
var removedFromMyArray = myArray.pop();
|
|
```
|
|
|
|
</section>
|