79d9012432
* fix(curriculum): tests quotes * fix(curriculum): fill seed-teardown * fix(curriculum): fix tests and remove unneeded seed-teardown
80 lines
2.5 KiB
Markdown
80 lines
2.5 KiB
Markdown
---
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id: 56bbb991ad1ed5201cd392cc
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title: Manipulate Arrays With pop()
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challengeType: 1
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---
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## Description
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<section id='description'>
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Another way to change the data in an array is with the <code>.pop()</code> function.
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<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.
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Any type of entry can be "popped" off of an array - numbers, strings, even nested arrays.
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<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>
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</section>
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## Instructions
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<section id='instructions'>
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Use the <code>.pop()</code> function to remove the last item from <code>myArray</code>, assigning the "popped off" value to <code>removedFromMyArray</code>.
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</section>
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## Tests
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<section id='tests'>
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```yml
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tests:
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- text: <code>myArray</code> should only contain <code>[["John", 23]]</code>.
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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>.');
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- text: Use <code>pop()</code> on <code>myArray</code>
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testString: assert(/removedFromMyArray\s*=\s*myArray\s*.\s*pop\s*(\s*)/.test(code), 'Use <code>pop()</code> on <code>myArray</code>');
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- text: <code>removedFromMyArray</code> should only contain <code>["cat", 2]</code>.
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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>.');
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```
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</section>
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## Challenge Seed
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<section id='challengeSeed'>
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<div id='js-seed'>
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```js
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// Example
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var ourArray = [1,2,3];
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var removedFromOurArray = ourArray.pop();
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// removedFromOurArray now equals 3, and ourArray now equals [1,2]
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// Setup
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var myArray = [["John", 23], ["cat", 2]];
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// Only change code below this line.
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var removedFromMyArray;
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```
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</div>
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### After Test
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<div id='js-teardown'>
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```js
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(function(y, z){return 'myArray = ' + JSON.stringify(y) + ' & removedFromMyArray = ' + JSON.stringify(z);})(myArray, removedFromMyArray);
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```
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</div>
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</section>
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## Solution
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<section id='solution'>
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```js
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var myArray = [["John", 23], ["cat", 2]];
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var removedFromMyArray = myArray.pop();
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```
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</section>
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