diff --git a/snippets/sampleSize.md b/snippets/sampleSize.md new file mode 100644 index 000000000..f6187bdea --- /dev/null +++ b/snippets/sampleSize.md @@ -0,0 +1,23 @@ +### sampleSize + +Gets `n` random elements at unique keys from `array` up to the size of `array`. + +Shuffle the array using the [Fisher-Yates algorithm](https://github.com/chalarangelo/30-seconds-of-code#shuffle). +Use `Array.slice()` to get the first `n` elements. +Omit the second argument, `n` to get only one element at random from the array. + +```js +const sampleSize = ([...arr],n=1) => { + let m = arr.length; + while (m) { + const i = Math.floor(Math.random() * m--); + [arr[m], arr[i]] = [arr[i], arr[m]]; + } + return arr.slice(0,n) +} +``` + +```js +sampleSize([1,2,3],2); // [3,1] +sampleSize([1,2,3],4); // [2,3,1] +```