下面代码,分别比较了 fmt.Sprintf,string +,strings.Join,bytes.Buffer,方法是循环若干次比较总时间。
性能由高到低依次是(bytes.Buffer) > (string +) > (fmt.Sprintf) > strings.Join
性能由高到低依次是(bytes.Buffer) > (string +) > (fmt.Sprintf) > strings.Join
测试代码如下:
package main import ( "bytes" "fmt" "strings" "time" ) func benchmarkStringFunction(n int, index int) (d time.Duration) { v := "abcd efg hijk lmn" var s string var buf bytes.Buffer t0 := time.Now() for i := 0; i < n; i++ { switch index { case 0: // fmt.Sprintf s = fmt.Sprintf("%s[%s]", s, v) case 1: // string + s = s + "[" + v + "]" case 2: // strings.Join s = strings.Join([]string{s, "[", v, "]"}, "") case 3: // temporary bytes.Buffer b := bytes.Buffer{} b.WriteString("[") b.WriteString(v) b.WriteString("]") s = b.String() case 4: // stable bytes.Buffer buf.WriteString("[") buf.WriteString(v) buf.WriteString("]") } if i == n-1 { if index == 4 { // for stable bytes.Buffer s = buf.String() } fmt.Println(len(s)) // consume s to avoid compiler optimization } } t1 := time.Now() d = t1.Sub(t0) fmt.Printf("time of way(%d)=%v\n", index, d) return d } func main() { k := 5 d := [5]time.Duration{} for i := 0; i < k; i++ { d[i] = benchmarkStringFunction(10000, i) } for i := 0; i < k-1; i++ { fmt.Printf("way %d is %6.1f times of way %d\n", i, float32(d[i])/float32(d[k-1]), k-1) } }
结果:
410000 time of way(0)=697.113743ms 410000 time of way(1)=455.614054ms 410000 time of way(2)=1.08289487s 41 time of way(3)=2.154884ms 410000 time of way(4)=792.74µs way 0 is 879.4 times of way 4 way 1 is 574.7 times of way 4 way 2 is 1366.0 times of way 4 way 3 is 2.7 times of way 4