20 lines
392 B
Markdown
20 lines
392 B
Markdown
---
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title: intersection
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tags: array,math,intermediate
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---
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Returns the elements that exist in both arrays.
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- Create a `Set` from `b`, then use `Array.prototype.filter()` on `a` to only keep values contained in `b`.
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```js
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const intersection = (a, b) => {
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const s = new Set(b);
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return [...new Set(a)].filter(x => s.has(x));
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};
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```
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```js
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intersection([1, 2, 3], [4, 3, 2]); // [2, 3]
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```
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