通过将 string 和 slice 转换为runtime 中的 slice 和 stringStruct 类型 然后 通过 指针获取下标的值。
```go
package main
import (
"fmt"
"unsafe"
)
type slice struct {
array unsafe.Pointer
len int
cap int
}
type stringStruct struct {
str unsafe.Pointer
len int
}
func main() {
///// string ////
str := "hello"
strStruct := (*stringStruct)(unsafe.Pointer(&str))
for i := 0; i < strStruct.len; i++ {
fmt.Printf("%c ", *(*byte)(unsafe.Pointer(uintptr(strStruct.str) + uintptr(i)*unsafe.Sizeof(byte(0))))) // 获取每字节的值
}
fmt.Printf("\n-----------------\n")
//// slice ////
bytes := []byte("Hello, 世界")
bytesSlice := (*slice)(unsafe.Pointer(&bytes))
for i := 0; i < bytesSlice.len; i++ {
fmt.Printf("%d ", *(*byte)(unsafe.Pointer(uintptr(bytesSlice.array) + uintptr(i)*unsafe.Sizeof(byte(0)))))
}
fmt.Printf("\n-----------------\n")
int8s := []int8{0, 9, 8, 7, 6, 90, 89, 87}
int8sSlice := (*slice)(unsafe.Pointer(&int8s))
for i := 0; i < int8sSlice.len; i++ {
fmt.Printf("%d ", *(*int8)(unsafe.Pointer(uintptr(int8sSlice.array) + uintptr(i)*unsafe.Sizeof(int8(0)))))
}
fmt.Printf("\n-----------------\n")
int16s := []int16{0, 9, 8, 7, 6, 90, 89, 87, 800}
int16Slice := (*slice)(unsafe.Pointer(&int16s))
for i := 0; i < int16Slice.len; i++ {
fmt.Printf("%d ", *(*int16)(unsafe.Pointer(uintptr(int16Slice.array) + uintptr(i)*unsafe.Sizeof(int16(0)))))
}
fmt.Printf("\n-----------------\n")
strings := []string{"hello", "世界", "golang"}
stringsSlice := (*slice)(unsafe.Pointer(&strings))
for i := 0; i < stringsSlice.len; i++ {
fmt.Printf("%s ", *(*string)(unsafe.Pointer(uintptr(stringsSlice.array) + uintptr(i)*unsafe.Sizeof(string(""))))) //unsafe.Sizeof(string(""))=16
}
fmt.Printf("\n-----------------\n")
}
```
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