79d9012432
* fix(curriculum): tests quotes * fix(curriculum): fill seed-teardown * fix(curriculum): fix tests and remove unneeded seed-teardown
73 lines
2.4 KiB
Markdown
73 lines
2.4 KiB
Markdown
---
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id: 56592a60ddddeae28f7aa8e1
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title: Access Multi-Dimensional Arrays With Indexes
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challengeType: 1
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guideUrl: 'https://www.freecodecamp.org/guide/certificates/access-array-data-with-indexes'
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---
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## Description
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<section id='description'>
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One way to think of a <dfn>multi-dimensional</dfn> array, is as an <em>array of arrays</em>. When you use brackets to access your array, the first set of brackets refers to the entries in the outer-most (the first level) array, and each additional pair of brackets refers to the next level of entries inside.
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<strong>Example</strong>
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<blockquote>var arr = [<br> [1,2,3],<br> [4,5,6],<br> [7,8,9],<br> [[10,11,12], 13, 14]<br>];<br>arr[3]; // equals [[10,11,12], 13, 14]<br>arr[3][0]; // equals [10,11,12]<br>arr[3][0][1]; // equals 11</blockquote>
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<strong>Note</strong><br>There shouldn't be any spaces between the array name and the square brackets, like <code>array [0][0]</code> and even this <code>array [0] [0]</code> is not allowed. Although JavaScript is able to process this correctly, this may confuse other programmers reading your code.
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</section>
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## Instructions
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<section id='instructions'>
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Using bracket notation select an element from <code>myArray</code> such that <code>myData</code> is equal to <code>8</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>myData</code> should be equal to <code>8</code>.
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testString: assert(myData === 8, '<code>myData</code> should be equal to <code>8</code>.');
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- text: You should be using bracket notation to read the correct value from <code>myArray</code>.
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testString: assert(/myArray\[2\]\[1\]/g.test(code) && !/myData\s*=\s*(?:.*[-+*/%]|\d)/g.test(code), 'You should be using bracket notation to read the correct value from <code>myArray</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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// Setup
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var myArray = [[1,2,3], [4,5,6], [7,8,9], [[10,11,12], 13, 14]];
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// Only change code below this line.
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var myData = myArray[0][0];
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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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if(typeof myArray !== "undefined"){(function(){return "myData: " + myData + " myArray: " + JSON.stringify(myArray);})();}
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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 = [[1,2,3],[4,5,6], [7,8,9], [[10,11,12], 13, 14]];
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var myData = myArray[2][1];
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```
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</section>
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