写到Golang缓冲区的开头？

Question

I have:

var buffer bytes.Buffer
s := "something to do"
for i := 0; i < 10; i++ {
   buffer.WriteString(s)
}

Which appends to the buffer, is it possible to write to the beginning of a buffer?

Answer 1

Since the underlying buf not exported from bytes.Buffer, you may use:

buffer.WriteString("B")
s := buffer.String()
buffer.Reset()
buffer.WriteString("A")
buffer.WriteString(s)

Try this The Go Playground:

package main

import (
    "bytes"
    "fmt"
)

func main() {
    var buffer bytes.Buffer
    buffer.WriteString("B")
    s := buffer.String()
    buffer.Reset()
    buffer.WriteString("A" + s)
    fmt.Println(buffer.String())
}

output:

AB