我想把字符串赋值给bytes数组:
var arr [20]byte
str := "abc"
for k, v := range []byte(str) {
arr[k] = byte(v)
}
还有别的方法吗?
当前回答
如果有人正在寻找一个快速考虑使用不安全转换片之间，可以参考下面的比较。
package demo_test
import (
"testing"
"unsafe"
)
var testStr = "hello world"
var testBytes = []byte("hello world")
// Avoid copying the data.
func UnsafeStrToBytes(s string) []byte {
return *(*[]byte)(unsafe.Pointer(&s))
}
// Avoid copying the data.
func UnsafeBytesToStr(b []byte) string {
return *(*string)(unsafe.Pointer(&b))
}
func Benchmark_UnsafeStrToBytes(b *testing.B) {
for i := 0; i < b.N; i++ {
_ = UnsafeStrToBytes(testStr)
}
}
func Benchmark_SafeStrToBytes(b *testing.B) {
for i := 0; i < b.N; i++ {
_ = []byte(testStr)
}
}
func Benchmark_UnSafeBytesToStr(b *testing.B) {
for i := 0; i < b.N; i++ {
_ = UnsafeBytesToStr(testBytes)
}
}
func Benchmark_SafeBytesToStr(b *testing.B) {
for i := 0; i < b.N; i++ {
_ = string(testBytes)
}
}
go test -v -bench="^Benchmark" -run=none
输出
cpu: Intel(R) Core(TM) i7-8565U CPU @ 1.80GHz
Benchmark_UnsafeStrToBytes
Benchmark_UnsafeStrToBytes-8 1000000000 0.2465 ns/op
Benchmark_SafeStrToBytes
Benchmark_SafeStrToBytes-8 289119562 4.181 ns/op
Benchmark_UnSafeBytesToStr
Benchmark_UnSafeBytesToStr-8 1000000000 0.2530 ns/op
Benchmark_SafeBytesToStr
Benchmark_SafeBytesToStr-8 342842938 3.623 ns/op
PASS
其他回答
小菜一碟:
arr := []byte("That's all folks!!")
安全简单:
[]byte("Here is a string....")
我认为这样更好。
package main
import "fmt"
func main() {
str := "abc"
mySlice := []byte(str)
fmt.Printf("%v -> '%s'",mySlice,mySlice )
}
点击这里查看:http://play.golang.org/p/vpnAWHZZk7
除了上面提到的方法，你还可以做一个小技巧
s := "hello"
b := *(*[]byte)(unsafe.Pointer((*reflect.SliceHeader)(unsafe.Pointer(&s))))
Go Play: http://play.golang.org/p/xASsiSpQmC
你不应该使用这个:-)
如果有人正在寻找一个快速考虑使用不安全转换片之间，可以参考下面的比较。
package demo_test
import (
"testing"
"unsafe"
)
var testStr = "hello world"
var testBytes = []byte("hello world")
// Avoid copying the data.
func UnsafeStrToBytes(s string) []byte {
return *(*[]byte)(unsafe.Pointer(&s))
}
// Avoid copying the data.
func UnsafeBytesToStr(b []byte) string {
return *(*string)(unsafe.Pointer(&b))
}
func Benchmark_UnsafeStrToBytes(b *testing.B) {
for i := 0; i < b.N; i++ {
_ = UnsafeStrToBytes(testStr)
}
}
func Benchmark_SafeStrToBytes(b *testing.B) {
for i := 0; i < b.N; i++ {
_ = []byte(testStr)
}
}
func Benchmark_UnSafeBytesToStr(b *testing.B) {
for i := 0; i < b.N; i++ {
_ = UnsafeBytesToStr(testBytes)
}
}
func Benchmark_SafeBytesToStr(b *testing.B) {
for i := 0; i < b.N; i++ {
_ = string(testBytes)
}
}
go test -v -bench="^Benchmark" -run=none
输出
cpu: Intel(R) Core(TM) i7-8565U CPU @ 1.80GHz
Benchmark_UnsafeStrToBytes
Benchmark_UnsafeStrToBytes-8 1000000000 0.2465 ns/op
Benchmark_SafeStrToBytes
Benchmark_SafeStrToBytes-8 289119562 4.181 ns/op
Benchmark_UnSafeBytesToStr
Benchmark_UnSafeBytesToStr-8 1000000000 0.2530 ns/op
Benchmark_SafeBytesToStr
Benchmark_SafeBytesToStr-8 342842938 3.623 ns/op
PASS
