Extract regex capture groups

Inspect numbered and named capture groups for a regular expression match.

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ToolRegex Groups
Input
Output
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Preview

How it works

Capturing parentheses are indexed by opening order, named groups are collected by label, and a match records the full text plus each participating subgroup. An absent optional group produces an undefined capture.

  • Numbered groups preserve JavaScript compatibility.
  • Named groups make extracted fields readable.

Worked example

Extract year, month, day from ISO dates
Use capture groups to extract year, month, and day from a date string
Input
											Today is 2024-01-15 and tomorrow is 2024-01-16
Output
												Pattern: /(\w+)/g

Match 1: "Today"
  Group 1: "Today"
Match 2: "is"
  Group 1: "is"
Match 3: "2024"
  Group 1: "2024"
Match 4: "01"
  Group 1: "01"
Match 5: "15"
  Group 1: "15"
Match 6: "and"
  Group 1: "and"
Match 7: "tomorrow"
  Group 1: "tomorrow"
Match 8: "is"
  Group 1: "is"
Match 9: "2024"
  Group 1: "2024"
Match 10: "01"
  Group 1: "01"
Match 11: "16"
  Group 1: "16"

When to use this

Log parsing, URL extraction, and replacement templates inspect captures.

Edge cases

  • Adding a nested outer group changes later numbers.
  • An optional group can be absent.
  • A repeated capture retains only the last iteration.

References