mirror of
https://github.com/samber/lo.git
synced 2026-04-22 23:47:11 +08:00
Samuel Berthe
44 lines
1.1 KiB
Markdown
44 lines
1.1 KiB
Markdown
---
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name: PartitionBy
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slug: partitionby
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sourceRef: parallel/slice.go#L92
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category: parallel
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subCategory: slice
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playUrl: ""
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similarHelpers:
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- core#slice#partitionby
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- parallel#slice#groupby
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position: 40
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signatures:
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- "func PartitionBy[T any, K comparable, Slice ~[]T](collection Slice, iteratee func(item T) K) []Slice"
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variantHelpers:
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- parallel#slice#partitionby
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---
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Returns a slice of groups where contiguous elements sharing the same key are batched together. Groups are created from the results of running each element of the collection through the predicate. The predicate is called in parallel and the order of groups follows their first appearance in the collection.
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```go
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import (
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lop "github.com/samber/lo/parallel"
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)
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groups := lop.PartitionBy([]int{-2, -1, 0, 1, 2, 3, 4, 5}, func(x int) string {
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if x < 0 { return "negative" }
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if x%2 == 0 { return "even" }
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return "odd"
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})
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// [][]int{{-2, -1}, {0, 2, 4}, {1, 3, 5}}
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```
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Works with any comparable key type:
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```go
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type Bucket int
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parts := lop.PartitionBy([]int{1,2,2,3,3,3}, func(x int) Bucket {
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return Bucket(x)
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})
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// [][]int{{1}, {2,2}, {3,3,3}}
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```
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