子匹配中的正则表达式替换

Question

Given a string (a line in a log file):

Date=2017-06-29 03:10:01.140 -700 PDT,clientDataRate="12.0,18.0,24.0,36.0,48.0,54.0",host=superawesomehost.foo,foo=bar

I'd like to replace the commas with a single space, but only within double quotes.

Desired result:

Date=2017-06-29 03:10:01.140 -700 PDT,clientDataRate="12.0 18.0 24.0 36.0 48.0 54.0",host=superawesomehost.foo,foo=bar

I've begun with a basic combination of regex and ReplaceAllString but am rapidly realizing I don't understand how to implement the match group (?) needed to accomplish this.

package main

import (
    "fmt"
    "log"
    "regexp"
)

func main() {
    logLine := "Date=2017-06-29 03:10:01.140 -700 PDT,clientDataRate=\"12.0,18.0,24.0,36.0,48.0,54.0\",host=superawesomehost.foo,foo=bar"
    fmt.Println("logLine:        ", logLine)

    reg, err := regexp.Compile("[^A-Za-z0-9=\"-:]+")
        if err != nil {
                log.Fatal(err)
        }

    repairedLogLine := reg.ReplaceAllString(logLine, ",")
    fmt.Println("repairedLogLine:", repairedLogLine )   
}

All help is much appreciated.

Answer 1

You'll want to use Regexp.ReplaceAllStringFunc, which allows you to use a function result as the replacement of a substring:

package main

import (
    "fmt"
    "log"
    "regexp"
    "strings"
)

func main() {
    logLine := `Date=2017-06-29 03:10:01.140 -700 PDT,clientDataRate="12.0,18.0,24.0,36.0,48.0,54.0",host=superawesomehost.foo,foo=bar`
    fmt.Println("logLine:        ", logLine)

    reg, err := regexp.Compile(`"([^"]*)"`)
    if err != nil {
        log.Fatal(err)
    }

    repairedLogLine := reg.ReplaceAllStringFunc(logLine, func(entry string) string {
        return strings.Replace(entry, ",", " ", -1)
    })
    fmt.Println("repairedLogLine:", repairedLogLine)
}

https://play.golang.org/p/BsZxcrrvaR