Go字符串拼接6种方式及其性能测试：strings.builder最快

Go字符串拼接常见的方式有加号、fmt.Sprintf、strings.Builder、bytes.Buffer、strings.join、切片。

package concat_string

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

const numbers = 100

// +
func BenchmarkStringAdd(b *testing.B) {
  b.ResetTimer()
  for idx := 0; idx < b.N; idx++ {
    var s string
    for i := 0; i < numbers; i++ {
      s += strconv.Itoa(i)
    }

  }
  b.StopTimer()
}

// fmt.Sprintf
func BenchmarkSprintf(b *testing.B) {
  b.ResetTimer()
  for idx := 0; idx < b.N; idx++ {
    var s string
    for i := 0; i < numbers; i++ {
      s = fmt.Sprintf("%v%v", s, i)
    }
  }
  b.StopTimer()
}

// strings.Builder
func BenchmarkStringBuilder(b *testing.B) {
  b.ResetTimer()
  for idx := 0; idx < b.N; idx++ {
    var builder strings.Builder
    for i := 0; i < numbers; i++ {
      builder.WriteString(strconv.Itoa(i))

    }
    _ = builder.String()
  }
  b.StopTimer()
}

// bytes.Buffer
func BenchmarkBytesBuf(b *testing.B) {
  b.ResetTimer()
  for idx := 0; idx < b.N; idx++ {
    var buf bytes.Buffer
    for i := 0; i < numbers; i++ {
      buf.WriteString(strconv.Itoa(i))
    }
    _ = buf.String()
  }
  b.StopTimer()
}

// strings.join
func BenchmarkStringsJoin(b *testing.B) {
  b.ResetTimer()
  var strs []string
  for i := 0; i < b.N; i++ {
    strs = append(strs, strconv.Itoa(i))
  }
  _ = strings.Join(strs, "")
  b.StopTimer()
}

// 切片
func BenchmarkByteSliceString(b *testing.B) {
  b.ResetTimer()
  buf := make([]byte, 0)
  for i := 0; i < b.N; i++ {
    buf = append(buf, byte(i))
  }
  _ = string(buf)
  b.StopTimer()
}

go test -bench=.

​​244851 4725 ns/op​​ 表示单位时间内（默认是1s）被测函数运行了 244851次，每次运行耗时 4725ns

总耗时10.261s。

​​​http://t.zoukankan.com/yahuian-p-go-benchmark.html​​