Regex - extract string between double quotes where line starts with a keyword

user_9317334 0
Viewed 254

Given the following lines:

classes!("text-xl", "text-blue-500")
String::from("test")
classes!("text-sm")

I wish to extract text-xl, text-blue-500 and text-sm and potentially any other strings within classes!

What I have so far is:

  • (?<=classes!).* - this gives me everything after classes! but not the exact values
  • (?!^")".*?" - this gives me the values I want with but with the quotes
  • I use the global and multi line flags
javascript regex
2 Answers

If you are using Javascript, and the positive lookbehind is supported (you don't need the multiline flag, only the global flag)

(?<=classes!\((?:"[^"]*",\s*)*")[^"]*(?=")
  • (?<= Positive lookbehind to assert to the left
    • classes!\( Match classes!(
    • (?:"[^"]*",\s*)* Match optional repetitions of "...",
    • " Match a double quote
  • ) Close lookbehind
  • [^"]* Match optional chars other than "
  • (?=") Assert " to the right

Regex demo

const regex = /(?<=classes!\((?:"[^"]*",\s*)*")[^"]*(?=")/g;
const str = `classes!("text-xl", "text-blue-500")
String::from("test")
classes!("text-sm")
`;
console.log(str.match(regex))

user_54249880

You could try a non fixed-width lookbehind like so:

(?<=^classes!\("(?:[^"]*"[^"()]*")*)[^"]*

See an online demo

  • (?<= - Open a positive lookbehind;
    • ^classes!\(" - Start-line anchor and match literally 'classes!("';
    • (?:[^"]*"[^()"]*")* - A nested non-capture group to match (0+ times) any char other than quotes (and paranthesis), a quote and that same sequence repeated.
    • ) - Close lookbehind;
  • [^"]* - Match 0+ (Greedy) characters other than quotes.
user_97581940
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