bd68b70f3d
* fix: remove isHidden flag from frontmatter * fix: add isUpcomingChange Co-authored-by: Ahmad Abdolsaheb <ahmad.abdolsaheb@gmail.com> * feat: hide blocks not challenges Co-authored-by: Ahmad Abdolsaheb <ahmad.abdolsaheb@gmail.com> Co-authored-by: Ahmad Abdolsaheb <ahmad.abdolsaheb@gmail.com>
84 lines
2.2 KiB
Markdown
84 lines
2.2 KiB
Markdown
---
|
|
id: 56bbb991ad1ed5201cd392cc
|
|
title: Manipulate Arrays With pop()
|
|
challengeType: 1
|
|
videoUrl: 'https://scrimba.com/c/cRbVZAB'
|
|
forumTopicId: 18236
|
|
---
|
|
|
|
## 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.
|
|
|
|
```js
|
|
var threeArr = [1, 4, 6];
|
|
var oneDown = threeArr.pop();
|
|
console.log(oneDown); // Returns 6
|
|
console.log(threeArr); // Returns [1, 4]
|
|
```
|
|
|
|
</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));
|
|
- text: You should use <code>pop()</code> on <code>myArray</code>.
|
|
testString: assert(/removedFromMyArray\s*=\s*myArray\s*.\s*pop\s*(\s*)/.test(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));
|
|
|
|
```
|
|
|
|
</section>
|
|
|
|
## Challenge Seed
|
|
<section id='challengeSeed'>
|
|
|
|
<div id='js-seed'>
|
|
|
|
```js
|
|
// 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>
|