12 Capture the parts

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Goal

Match ISO dates like 2026-10-22, capturing the year, month and day as groups 1, 2 and 3.

Every pair of parentheses is also a capture group: it remembers the text it matched, numbered from 1 by its opening bracket. Code reads them back — in JavaScript, text.match(re)[1] is the year.

You can name them: (?<year>\d{4}). And if you need grouping without capturing, (?:…) groups silently.

Try it

Pull a date apart. Each group is highlighted in its own shade inside the match.

Go to the terminal

Hint

/^(\d{4})-(\d{2})-(\d{2})$/ — each pair of parentheses captures what it matched.

Show a solution

/^(\d{4})-(\d{2})-(\d{2})$/

This interactive environment needs JavaScript. Everything you need to read is on this page, and the solution works the same way for real.

Regex

Starting Regex…