[Go]slice→二次元slice

Go slice → 二次元slice

intの例

package main

import "fmt"

func main() {
	fmt.Println(to2D(makeSlice(12), 0))
	fmt.Println(to2D(makeSlice(30), 6))
	fmt.Println(to2D(makeSlice(40), 6))
	fmt.Println(to2D(makeSlice(37), 8))
}

func makeSlice(n int) []int {
	res := make([]int, n)
	for i := 0; i < n; i++ {
		res[i] = i
	}
	return res
}

func to2D(s []int, n int) [][]int {
	res := make([][]int, 0)
	if len(s) == 0 || n == 0 {
		return res
	}
	c := len(s) / n
	loop := c
	if len(s)%n != 0 {
		loop += 1
	}

	for i := 0; i < loop; i++ {
		tmp := make([]int, 0)
		for j := 0; j < n; j++ {
			idx := i*n + j
			if idx == len(s) {
				break
			}
			tmp = append(tmp, s[idx])
		}
		if len(tmp) != 0 {
			res = append(res, tmp)
		}
	}
	return res
}

output

[]
[[0 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]]
[[0 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]]
[[0 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]]

Genericsの例

1.18から追加されたGenericsを使って書き直すと、嬉しい

package main

import "fmt"

func main() {
	fmt.Println(anyTo2D(makeStringSlice("abcdefghijklmnopqrstuvwxyz"), 5))
	fmt.Println(anyTo2D(makeRuneSlice("abcdefghijklmnopqrstuvwxyz"), 6))
}

func makeStringSlice(s string) []string {
	dist := make([]string, 0)
	for _, r := range s {
		dist = append(dist, string(r))
	}
	return dist
}

func makeRuneSlice(s string) []rune {
	dist := make([]rune, 0)
	for _, r := range s {
		dist = append(dist, r)
	}
	return dist
}

func anyTo2D[G any](s []G, n int) [][]G {
	res := make([][]G, 0)
	if len(s) == 0 || n == 0 {
		return res
	}
	c := len(s) / n
	loop := c
	if len(s)%n != 0 {
		loop += 1
	}

	for i := 0; i < loop; i++ {
		tmp := make([]G, 0)
		for j := 0; j < n; j++ {
			idx := i*n + j
			if idx == len(s) {
				break
			}
			tmp = append(tmp, s[idx])
		}
		if len(tmp) != 0 {
			res = append(res, tmp)
		}
	}
	return res
}

output

[[a b c d e] [f g h i j] [k l m n o] [p q r s t] [u v w x y] [z]]
[[97 98 99 100 101 102] [103 104 105 106 107 108] [109 110 111 112 113 114] [115 116 117 118 119 120] [121 122]]