Golang regexp to match multiple patterns between keyword pairs

Question

I have a string which has two keywords: "CURRENT NAME(S)" and "NEW NAME(S)" and each of these keywords are followed by a bunch of words. I want to extract those set of words beyond each of these keywords. To elaborate with a code:

    s := `"CURRENT NAME(S)
 Name1, Name2",,"NEW NAME(S)
NewName1,NewName2"`
    re := regexp.MustCompile(`"CURRENT NAME(S).*",,"NEW NAME(S).*"`)

    segs := re.FindAllString(s, -1)
    fmt.Println("segs:", segs)

    segs2 := re.FindAllStringSubmatch(s, -1)
    fmt.Println("segs2:", segs2)

As you can see, the string 's' has the input. "Name1,Name2" is the current names list and "NewName1, NewName2" is the new names list. I want to extract these two lists. The two lists are separated by a comma. Each of the keywords are beginning with a double quote and their reach ends, when their corresponding double quote ends.

What is the way to use regexp such that the program can print "Name1, Name2" and "NewName1,NewName2" ?

Answer 1

The issue with your regex is that the input string contains newline symbols, and . in Go regex does not match a newline. Another issue is that the .* is a greedy pattern and will match as many symbols as it can up to the last second keyword. Also, you need to escape parentheses in the regex pattern to match the ( and ) literal symbols.

The best way to solve the issue is to change .* into a negated character class pattern [^"]* and place it inside a pair of non-escaped ( and ) to form a capturing group (a construct to get submatches from the match).

Here is a Go demo:

package main

import (
    "fmt"
    "regexp"
)

func main() {
    s := `"CURRENT NAME(S)
 Name1, Name2",,"NEW NAME(S)
NewName1,NewName2"`
    re := regexp.MustCompile(`"CURRENT NAME\(S\)\s*([^"]*)",,"NEW NAME\(S\)\s*([^"]*)"`)

    segs2 := re.FindAllStringSubmatch(s,-1)
    fmt.Printf("segs2: [%s; %s]", segs2[0][1], segs2[0][2])
}

Now, the regex matches:

• "CURRENT NAME\(S\) - a literal string "CURRENT NAME(S)`
• \s* - zero or more whitespaces
• ([^"]*) - Group 1 capturing 0+ chars other than "
• ",,"NEW NAME\(S\) - a literal string ",,"NEW NAME(S)
• \s* - zero or more whitespaces
• ([^"]*) - Group 2 capturing 0+ chars other than "
• " - a literal "