78 lines
2.3 KiB
Markdown
78 lines
2.3 KiB
Markdown
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---
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id: 56533eb9ac21ba0edf2244e1
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title: Nesting For Loops
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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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If you have a multi-dimensional array, you can use the same logic as the prior waypoint to loop through both the array and any sub-arrays. Here is an example:
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<blockquote>var arr = [<br> [1,2], [3,4], [5,6]<br>];<br>for (var i=0; i < arr.length; i++) {<br> for (var j=0; j < arr[i].length; j++) {<br> console.log(arr[i][j]);<br> }<br>}</blockquote>
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This outputs each sub-element in <code>arr</code> one at a time. Note that for the inner loop, we are checking the <code>.length</code> of <code>arr[i]</code>, since <code>arr[i]</code> is itself an array.
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</section>
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## Instructions
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<section id='instructions'>
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Modify function <code>multiplyAll</code> so that it multiplies the <code>product</code> variable by each number in the sub-arrays of <code>arr</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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- text: '<code>multiplyAll([[1],[2],[3]])</code> should return <code>6</code>'
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testString: 'assert(multiplyAll([[1],[2],[3]]) === 6, "<code>multiplyAll([[1],[2],[3]])</code> should return <code>6</code>");'
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- text: '<code>multiplyAll([[1,2],[3,4],[5,6,7]])</code> should return <code>5040</code>'
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testString: 'assert(multiplyAll([[1,2],[3,4],[5,6,7]]) === 5040, "<code>multiplyAll([[1,2],[3,4],[5,6,7]])</code> should return <code>5040</code>");'
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- text: '<code>multiplyAll([[5,1],[0.2, 4, 0.5],[3, 9]])</code> should return <code>54</code>'
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testString: 'assert(multiplyAll([[5,1],[0.2, 4, 0.5],[3, 9]]) === 54, "<code>multiplyAll([[5,1],[0.2, 4, 0.5],[3, 9]])</code> should return <code>54</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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function multiplyAll(arr) {
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var product = 1;
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// Only change code below this line
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// Only change code above this line
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return product;
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}
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// Modify values below to test your code
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multiplyAll([[1,2],[3,4],[5,6,7]]);
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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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function multiplyAll(arr) {
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var product = 1;
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for (var i = 0; i < arr.length; i++) {
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for (var j = 0; j < arr[i].length; j++) {
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product *= arr[i][j];
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}
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}
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return product;
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}
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multiplyAll([[1,2],[3,4],[5,6,7]]);
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```
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</section>
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