doucan1979
doucan1979
2013-09-28 08:45

用golang解析Perl正则表达式

已采纳

http://play.golang.org/p/GM0SWo0qGs

This is my code and playground.

func insert_comma(input_num int) string {
    temp_str := strconv.Itoa(input_num)
    var validID = regexp.MustCompile(`\B(?=(\d{3})+$)`)
    return validID.ReplaceAllString(temp_str, ",")
}

 func main() {
    fmt.Println(insert_comma(1000000000))
 }

Basically, my desired input is 1,000,000,000. And the regular expression works in Javascript but I do not know how to make this Perl regex work in Go. I would greatly appreciate it. Thanks,

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1条回答

  • dougong2005 dougong2005 8年前

    Since lookahead assertion seems to be not supported, I'm providing you a different algorithm with no regexp:

    Perl code:

    sub insert_comma {
        my $x=shift;
        my $l=length($x);
        for (my $i=$l%3==0?3:$l%3;$i<$l;$i+=3) {
            substr($x,$i++,0)=',';
        }
        return $x;
    }
    print insert_comma(1000000000);
    

    Go code: Disclaimer: I have zero experience with Go, so bear with me if I have errors and feel free to edit my post!

    func insert_comma(input_num int) string {
        temp_str := strconv.Itoa(input_num)
        var result []string
        i := len(temp_str)%3;
        if i == 0 { i = 3 }
        for index,element := range strings.Split(temp_str, "") {
            if i == index {
                result = append(result, ",");
                i += 3;
            }
            result = append(result, element)
        }
        return strings.Join(result, "")
    }
    
    func main() {
        fmt.Println(insert_comma(1000000000))
    }
    

    http://play.golang.org/p/7pvo7-3G-s

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