Golang String 串接 PK 戰 - Golang String Concat / Buffer / Join / Copy / Append Performance Comparison

main_test.go

package main

import (
	"bytes"
	"fmt"
	"strconv"
	"strings"
	"testing"
)

// test only benchmarks use "go test -bench . -run=^$"
/* Result in My Macbook 2.7g i5
BenchmarkConcat-4   	 1000000	     85240 ns/op
BenchmarkBuffer-4   	100000000	        13.8 ns/op
BenchmarkJoin-4     	 5000000	       235 ns/op
BenchmarkCopy-4     	300000000	         4.81 ns/op
BenchmarkAppend-4   	300000000	         4.81 ns/op
*/

func TestCopy(t *testing.T) {
	bs := []byte{}
	for n := 0; n < 10; n++ {
		app := []byte{strconv.Itoa(n)[0]}
		bs = append(bs, app...)
	}
	fmt.Println(string(bs))
}

func BenchmarkConcat(b *testing.B) {
	var str string
	x := "x"
	for n := 0; n < b.N; n++ {
		str += x
	}
}

func BenchmarkBuffer(b *testing.B) {
	var buffer bytes.Buffer
	x := "x"
	for n := 0; n < b.N; n++ {
		buffer.WriteString(x)
	}
	_ = buffer.String()
}

func BenchmarkJoin(b *testing.B) {
	s := []string{}
	x := "x"
	for n := 0; n < b.N; n++ {
		s = append(s, x)
	}
	_ = strings.Join(s, "")
}

// Limit Length
func BenchmarkCopy(b *testing.B) {
	bs := make([]byte, b.N)
	bl := 0
	x := "x"
	for n := 0; n < b.N; n++ {
		bl += copy(bs[bl:], x)
	}
	_ = string(bs)
}

// Dynamic Length
func BenchmarkAppend(b *testing.B) {
	bs := []byte{}
	x := "x"
	for n := 0; n < b.N; n++ {
		bs = append(bs, x...)
	}
	_ = string(bs)
}