使用来自Go正则表达式的命名匹配

Question

I'm coming from python, so I'm probably just not looking at this the right way. I'd like to create a fairly complicated regex and be able to access the fields match by name. I can't seem to find a good example. The closest I've managed to get is this:

package main

import (
  "fmt"
  "regexp"
)

var myExp = regexp.MustCompile(`(?P<first>\d+)\.(\d+).(?P<second>\d+)`)

func main() {
  fmt.Printf("%+v", myExp.FindStringSubmatch("1234.5678.9"))

  match := myExp.FindStringSubmatch("1234.5678.9")
    for i, name := range myExp.SubexpNames() {
        fmt.Printf("'%s'\t %d -> %s
", name, i, match[i])
    }
    //fmt.Printf("by name: %s %s
", match["first"], match["second"])
}

The commented out line is how I would expect to access the named fields in python. What's the equivalent way to do this in go? Or if I need to convert the match to a map, what's the most idiomatic way in go to make and then access the map?

Answer 1

You can reference your named capture groups by utilizing map as follows:

package main

import (
    "fmt"
    "regexp"
)

var myExp = regexp.MustCompile(`(?P<first>\d+)\.(\d+).(?P<second>\d+)`)

func main() {
    match := myExp.FindStringSubmatch("1234.5678.9")
    result := make(map[string]string)
    for i, name := range myExp.SubexpNames() {
        if i != 0 && name != "" {
            result[name] = match[i]
        }
    }
    fmt.Printf("by name: %s %s
", result["first"], result["second"])
}

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