Golang截取字符串方法示例讲解及对比

func BenchmarkSubstr1(b *testing.B) {
	s := "bench基准测试，1212"
	for i := 0; i < b.N; i++ {
		s1 := []rune(s)
		s2 := s1[1:6]
		_ = string(s2)
	}
}

func DecodeRuneInString(s string) (r rune, size int)

func BenchmarkSubstr2(b *testing.B) {
	s := "bench基准测试，1212"
	st := 1
	en := 6
	for i := 0; i < b.N; i++ {
		var start, end int
		var c int
		for i := 0; i <= en && c < len(s); i++ {
			_, size := utf8.DecodeRuneInString(s[c:])
			if i == st {
				start = c
			}
			if i == en {
				end = c
			}
			c += size
		}
		_ = s[start:end]
	}
}

func TestSubstr(t *testing.T) {
	s := "bench基准测试，1212"
	for k, v := range s {
		fmt.Println(k, string(v))
	}
}

func TestSubstr(t *testing.T) {
	s := "bench基准测试，1212"
	var start, end int
	var c int
	for k := range s {
		if c == 1 {
			start = k
		}
		if c == 6 {
			end = k
		}
		c++
	}
	fmt.Println(s[start:end]) // ench基
}

func BenchmarkSubstr3(b *testing.B) {
	s := "bench基准测试，1212"
	for i := 0; i < b.N; i++ {
		var start, end int
		var c int
		for k := range s {
			if c == 1 {
				start = k
			}
			if c == 6 {
				end = k
			}
			c++
		}
		_ = s[start:end]
	}
}