golang 字符串技巧分享(1)--分割

引

开发过程中少不了要于字符串打交道。假如要对一个文本串进行分段，分割符是.?;. 还要保留分割符号，就不能使用常用的 string.Split 函数，Split 会把分割符去除。下面介绍两种方式。

基于状态方法

用时 2:42

package main

import (
    "fmt"
)

func main() {
    const input = "1,2,3,4,5;6.7?"
    var all []string

    prev := 0
    for i := 0; i < len(input); i++ {
        switch input[i] {
        case ',', '.', ';', '?':
            all = append(all, input[prev:i+1])
            prev = i + 1 
        }
    }   

    for _, v := range all {
        fmt.Printf("%s\n", v)
    }   
}

基于 scanner

用时 1:28(复制官网例子，修改回调函数的内容，所以用时很短)

package main

import (
    "bufio"
    "fmt"
    "os"
    "strings"
)

func main() {
    // Comma-separated list; last entry is empty.
    const input = "1,2,3,4,5;6.7?"
    scanner := bufio.NewScanner(strings.NewReader(input))
    // Define a split function that separates on commas.
    onComma := func(data []byte, atEOF bool) (advance int, token []byte, err error) {
        for i := 0; i < len(data); i++ {
            switch data[i] {
            case ',', '.', ';', '?':
                return i + 1, data[:i+1], nil 
            }   
        }
        if !atEOF {
            return 0, nil, nil 
        }   
        // There is one final token to be delivered, which may be the empty string.
        // Returning bufio.ErrFinalToken here tells Scan there are no more tokens after this
        // but does not trigger an error to be returned from Scan itself.
        return 0, data, bufio.ErrFinalToken
    }   
    scanner.Split(onComma)
    // Scan.
    for scanner.Scan() {
        fmt.Printf("%q ", scanner.Text())
    }   
    if err := scanner.Err(); err != nil {
        fmt.Fprintln(os.Stderr, "reading input:", err)
    }   
}

交流学习

上面两种方式都把编码时间写上，欢迎 v 贴出自己的方法，互相学习。

github

https://github.com/guonaihong/gout