27 lines
692 B
Markdown
27 lines
692 B
Markdown
---
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title: sampleSize
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tags: array,random,intermediate
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---
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Gets `n` random elements at unique keys from `array` up to the size of `array`.
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- Shuffle the array using the [Fisher-Yates algorithm](https://github.com/30-seconds/30-seconds-of-code#shuffle).
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- Use `Array.prototype.slice()` to get the first `n` elements.
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- Omit the second argument, `n` to get only one element at random from the array.
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```js
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const sampleSize = ([...arr], n = 1) => {
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let m = arr.length;
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while (m) {
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const i = Math.floor(Math.random() * m--);
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[arr[m], arr[i]] = [arr[i], arr[m]];
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}
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return arr.slice(0, n);
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};
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```
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```js
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sampleSize([1, 2, 3], 2); // [3,1]
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sampleSize([1, 2, 3], 4); // [2,3,1]
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```
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