1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
|
// Copyright 2019 The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
// Package slices implements various slice algorithms.
package slices
// Map turns a []T1 to a []T2 using a mapping function.
func Map[T1, T2 any](s []T1, f func(T1) T2) []T2 {
r := make([]T2, len(s))
for i, v := range s {
r[i] = f(v)
}
return r
}
// Reduce reduces a []T1 to a single value using a reduction function.
func Reduce[T1, T2 any](s []T1, initializer T2, f func(T2, T1) T2) T2 {
r := initializer
for _, v := range s {
r = f(r, v)
}
return r
}
// Filter filters values from a slice using a filter function.
func Filter[T any](s []T, f func(T) bool) []T {
var r []T
for _, v := range s {
if f(v) {
r = append(r, v)
}
}
return r
}
// Example uses
func limiter(x int) byte {
switch {
case x < 0:
return 0
default:
return byte(x)
case x > 255:
return 255
}
}
var input = []int{-4, 68954, 7, 44, 0, -555, 6945}
var limited1 = Map[int, byte](input, limiter)
var limited2 = Map(input, limiter) // using type inference
func reducer(x float64, y int) float64 {
return x + float64(y)
}
var reduced1 = Reduce[int, float64](input, 0, reducer)
var reduced2 = Reduce(input, 1i, reducer) // using type inference
var reduced3 = Reduce(input, 1, reducer) // using type inference
func filter(x int) bool {
return x&1 != 0
}
var filtered1 = Filter[int](input, filter)
var filtered2 = Filter(input, filter) // using type inference
|
