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Golang中操作[]byte类型的Trim函数

Posted on 2014-03-10 23:47:03 golang

在Golang中字符串的一个坑这篇博文中，介绍了Golang中字符串与C中的字符串的不同之处：C中的字符串是以\x0为结尾的字节序列，而Golang中的字符串则更严格，并不是以\x0为结尾来判断，而是计算字符串变量的值中的所有字节。

Golang中的字符串在打印时，因为\x0是不可打印字符，所以和C中的字符串在打印时没有任何区别。但是在一些需要按字节计算字符串的函数中，就会导致问题。通用的做法是，迭代字符串，只取得字节序列中的有效字节。

我们可以写一个函数来做这件事情，也可以用Golang的标准库中的bytes库。bytes库提供了对[]byte类型的操作，提供的接口和对string类型提供的接口类似。

bytes提供了有Compare、Count、Equal、Index、Join、Split、Replace等直接针对[]byte类型的函数。还有一个重要的Buffer类，将[]byte类型当作一个缓冲区，提供了对这个缓冲区便捷的操作：读、写、和string/rune之间的转换、迭代等函数。

在bytes库中，有Trim系列的函数，它的功能是对[]byte类型做裁剪，去除不需要的部分。

func Trim(s []byte, cutset string) []byte
func TrimFunc(s []byte, f func(r rune) bool) []byte
func TrimLeft(s []byte, cutset string) []byte
func TrimLeftFunc(s []byte, f func(r rune) bool) []byte
func TrimPrefix(s, prefix []byte) []byte
func TrimRight(s []byte, cutset string) []byte
func TrimRightFunc(s []byte, f func(r rune) bool) []byte
func TrimSpace(s []byte) []byte
func TrimSuffix(s, suffix []byte) []byte

我们需要使用TrimRight函数，将字节序列中不可打印的\x0字符剔除，只保留需要的：

package main

import (
    "bytes"
    "fmt"
)

func main() {
    var a [10]byte = [10]byte{1, 2, 3}
    fmt.Printf("%q\n", a)
    // 将数组a转换为切片
    b := a[:]
    // 去除切片尾部的所有0
    c := bytes.TrimRight(b, "\x00")
    fmt.Printf("%q\n", c)
}

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