64 lines
2.8 KiB
Markdown
64 lines
2.8 KiB
Markdown
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---
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id: 587d78b2367417b2b2512b10
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title: Remove Items Using splice()
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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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Ok, so we've learned how to remove elements from the beginning and end of arrays using <code>shift()</code> and <code>pop()</code>, but what if we want to remove an element from somewhere in the middle? Or remove more than one element at once? Well, that's where <code>splice()</code> comes in. <code>splice()</code> allows us to do just that: <strong>remove any number of consecutive elements</strong> from anywhere in an array.
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<code>splice()</code> can take up to 3 parameters, but for now, we'll focus on just the first 2. The first two parameters of <code>splice()</code> are integers which represent indexes, or positions, of the array that <code>splice()</code> is being called upon. And remember, arrays are <em>zero-indexed</em>, so to indicate the first element of an array, we would use <code>0</code>. <code>splice()</code>'s first parameter represents the index on the array from which to begin removing elements, while the second parameter indicates the number of elements to delete. For example:
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<blockquote>let array = ['today', 'was', 'not', 'so', 'great'];<br><br>array.splice(2, 2);<br>// remove 2 elements beginning with the 3rd element<br>// array now equals ['today', 'was', 'great']</blockquote>
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<code>splice()</code> not only modifies the array it's being called on, but it also returns a new array containing the value of the removed elements:
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<blockquote>let array = ['I', 'am', 'feeling', 'really', 'happy'];<br><br>let newArray = array.splice(3, 2);<br>// newArray equals ['really', 'happy']</blockquote>
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</section>
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## Instructions
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<section id='instructions'>
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We've defined a function, <code>sumOfTen</code>, which takes an array as an argument and returns the sum of that array's elements. Modify the function, using <code>splice()</code>, so that it returns a value of <code>10</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>sumOfTen</code> should return 10
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testString: 'assert.strictEqual(sumOfTen([2, 5, 1, 5, 2, 1]), 10, "<code>sumOfTen</code> should return 10");'
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- text: The <code>sumOfTen</code> function should utilize the <code>splice()</code> method
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testString: 'assert.notStrictEqual(sumOfTen.toString().search(/\.splice\(/), -1, "The <code>sumOfTen</code> function should utilize the <code>splice()</code> method");'
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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 sumOfTen(arr) {
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// change code below this line
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// change code above this line
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return arr.reduce((a, b) => a + b);
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}
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// do not change code below this line
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console.log(sumOfTen([2, 5, 1, 5, 2, 1]));
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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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// solution required
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```
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</section>
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