array_delete_test.go

package main

import (
	"testing"
)

const ARRAY_SIZE = 100000

func mkArray() []int {
	arr := make([]int, ARRAY_SIZE)
	for i := 0; i < ARRAY_SIZE; i++ {
		arr[i] = i
	}
	return arr
}

func BenchmarkUseAppend(b *testing.B) {
	arrays := make([][]int, b.N)
	for i := 0; i < b.N; i++ {
		arrays[i] = mkArray()
	}
	b.ResetTimer()
	idx := 0
	for i := 0; i < b.N; i++ {
		arr := arrays[i]
		for len(arr) > 0 {
			arr = append(arr[:idx], arr[idx+1:]...)
		}
	}
}

func BenchmarkUseManualCopy(b *testing.B) {
	arrays := make([][]int, b.N)
	for i := 0; i < b.N; i++ {
		arrays[i] = mkArray()
	}
	b.ResetTimer()
	idx := 0
	for i := 0; i < b.N; i++ {
		arr := arrays[i]
		for len(arr) > 0 {
			for j := idx; j < len(arr)-1; j++ {
				arr[j] = arr[j+1]
			}
			arr = arr[:len(arr)-1]
		}
	}
}

func BenchmarkUseCopy(b *testing.B) {
	arrays := make([][]int, b.N)
	for i := 0; i < b.N; i++ {
		arrays[i] = mkArray()
	}
	b.ResetTimer()
	idx := 0
	for i := 0; i < b.N; i++ {
		arr := arrays[i]
		for len(arr) > 0 {
			copy(arr[idx:], arr[idx+1:])
			arr = arr[:len(arr)-1]
		}
	}
}

result.txt

❯ go test -bench . -benchmem
goos: windows
goarch: amd64
pkg: gist.github.com/Maki-Daisuke/go-bench-array-delete
cpu: 13th Gen Intel(R) Core(TM) i7-13700F
BenchmarkUseAppend-24                  3         492529833 ns/op               0 B/op          0 allocs/op
BenchmarkUseManualCopy-24              1        1230478800 ns/op               0 B/op          0 allocs/op
BenchmarkUseCopy-24                    3         489893567 ns/op               0 B/op          0 allocs/op
PASS
ok      gist.github.com/Maki-Daisuke/go-bench-array-delete      7.988s