21 lines
530 B
Markdown
21 lines
530 B
Markdown
---
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title: cartesianProduct
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tags: math,array,beginner
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firstSeen: 2020-12-28T20:23:47+02:00
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lastUpdated: 2020-12-29T12:31:43+02:00
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---
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Calculates the cartesian product of two arrays.
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- Use `Array.prototype.reduce()`, `Array.prototype.map()` and the spread operator (`...`) to generate all possible element pairs from the two arrays.
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```js
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const cartesianProduct = (a, b) =>
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a.reduce((p, x) => [...p, ...b.map(y => [x, y])], []);
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```
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```js
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cartesianProduct(['x', 'y'], [1, 2]);
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// [['x', 1], ['x', 2], ['y', 1], ['y', 2]]
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```
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