35 lines
1.0 KiB
Markdown
35 lines
1.0 KiB
Markdown
---
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title: Pull values from array at index
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type: snippet
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language: javascript
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tags: [array]
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cover: cave-exploration
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dateModified: 2020-10-22T20:24:04+03:00
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---
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Mutates the original array to filter out the values at the specified indexes.
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Returns the removed elements.
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- Use `Array.prototype.filter()` and `Array.prototype.includes()` to pull out the values that are not needed.
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- Set `Array.prototype.length` to mutate the passed in an array by resetting its length to `0`.
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- Use `Array.prototype.push()` to re-populate it with only the pulled values.
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- Use `Array.prototype.push()` to keep track of pulled values.
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```js
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const pullAtIndex = (arr, pullArr) => {
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let removed = [];
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let pulled = arr
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.map((v, i) => (pullArr.includes(i) ? removed.push(v) : v))
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.filter((v, i) => !pullArr.includes(i));
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arr.length = 0;
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pulled.forEach(v => arr.push(v));
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return removed;
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};
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```
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```js
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let myArray = ['a', 'b', 'c', 'd'];
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let pulled = pullAtIndex(myArray, [1, 3]);
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// myArray = [ 'a', 'c' ] , pulled = [ 'b', 'd' ]
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```
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