54 lines
1.2 KiB
Markdown
54 lines
1.2 KiB
Markdown
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<!-- Note: This file is automatically generated from source code comments. Changes made in this file will be overridden. -->
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# Function partitionSelect
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Partition-based selection of an array or 1D matrix.
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Will find the kth smallest value, and mutates the input array.
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Uses Quickselect.
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## Syntax
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```js
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math.partitionSelect(x, k)
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math.partitionSelect(x, k, compare)
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```
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### Parameters
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Parameter | Type | Description
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--------- | ---- | -----------
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`x` | Matrix | Array | A one dimensional matrix or array to sort
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`k` | Number | The kth smallest value to be retrieved zero-based index
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`compare` | Function | 'asc' | 'desc' | An optional comparator function. The function is called as `compare(a, b)`, and must return 1 when a > b, -1 when a < b, and 0 when a == b. Default value: 'asc'.
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### Returns
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Type | Description
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---- | -----------
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* | Returns the kth lowest value.
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### Throws
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Type | Description
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---- | -----------
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## Examples
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```js
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math.partitionSelect([5, 10, 1], 2) // returns 10
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math.partitionSelect(['C', 'B', 'A', 'D'], 1) // returns 'B'
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function sortByLength (a, b) {
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return a.length - b.length
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}
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math.partitionSelect(['Langdon', 'Tom', 'Sara'], 2, sortByLength) // returns 'Langdon'
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```
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## See also
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[sort](sort.md)
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