17 lines
521 B
Markdown
17 lines
521 B
Markdown
---
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title: percentile
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tags: math,intermediate
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---
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Uses the percentile formula to calculate how many numbers in the given array are less or equal to the given value.
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Use `Array.prototype.reduce()` to calculate how many numbers are below the value and how many are the same value and apply the percentile formula.
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```js
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const percentile = (arr, val) =>
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(100 * arr.reduce((acc, v) => acc + (v < val ? 1 : 0) + (v === val ? 0.5 : 0), 0)) / arr.length;
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```
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```js
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percentile([1, 2, 3, 4, 5, 6, 7, 8, 9, 10], 6); // 55
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``` |