34 lines
992 B
Markdown
34 lines
992 B
Markdown
---
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title: Array is contained in other array
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tags: array
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expertise: intermediate
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author: chalarangelo
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cover: blog_images/island-corridor.jpg
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firstSeen: 2020-01-05T21:40:51+02:00
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lastUpdated: 2020-10-22T20:23:47+03:00
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---
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Checks if the elements of the first array are contained in the second one regardless of order.
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- Use a `for...of` loop over a `Set` created from the first array.
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- Use `Array.prototype.some()` to check if all distinct values are contained in the second array.
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- Use `Array.prototype.filter()` to compare the number of occurrences of each distinct value in both arrays.
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- Return `false` if the count of any element is greater in the first array than the second one, `true` otherwise.
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```js
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const isContainedIn = (a, b) => {
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for (const v of new Set(a)) {
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if (
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!b.some(e => e === v) ||
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a.filter(e => e === v).length > b.filter(e => e === v).length
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)
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return false;
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}
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return true;
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};
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```
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```js
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isContainedIn([1, 4], [2, 4, 1]); // true
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```
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