Go (RE2)

Named Capture Group (Date) in GO

Demonstrate named capture groups by extracting year/month/day from ISO-style dates.

Try it in the GO tester →

Pattern

regexGO
(?<year>\d{4})-(?<month>\d{2})-(?<day>\d{2})   (flags: g)

Go (RE2) code

goGo
package main

import (
	"fmt"
	"regexp"
)

func main() {
	re := regexp.MustCompile(`(?<year>\d{4})-(?<month>\d{2})-(?<day>\d{2})`)
	input := `Born 1990-05-21, hired 2018-09-10`
	for _, match := range re.FindAllString(input, -1) {
		fmt.Println(match)
	}
}

Uses `regexp.MustCompile` (panics on bad patterns at startup) and `FindAllString` for all matches.

How the pattern works

(?<year>\d{4}) captures four digits under the name 'year'; (?<month>\d{2}) and (?<day>\d{2}) likewise. Modern JS, Python 3.7+, and Go (with `(?P<...>)` syntax — JS-style is also accepted in Python 3.12+) all support this; the matched substring is accessible by name in code (e.g. m.groups.year in JS, m['year'] in Python).

Examples

Input

Born 1990-05-21, hired 2018-09-10

Matches

  • 1990-05-21
  • 2018-09-10

Input

Today is 2026-04-25

Matches

  • 2026-04-25

Input

no dates here

No match

—

Same pattern, other engines

JavaScript / ECMAScript

Supported

See how this pattern looks (and behaves) in JavaScript's built-in RegExp.

Python (re)

Supported

See how this pattern looks (and behaves) in Python's stdlib `re` module.

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