Feature: Backreferences

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Backreferences allow a pattern to re-match a previously matched capture group^{1 2} either by number (n) or by name.

Syntax

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NOTE: The following syntax is an example based on some of the supported engines. For specific engine support, see Engines.

• \n — Where n is a decimal digit in the range 1-9. Matches the same string as the capture group n.
• \k<name> — Matches the same string as the named capture group with the name name.

Engines

Engine	Supported
Perl	✔
PCRE	✔
Boost.Regex	✔
.NET	✔
Oniguruma	✔
Hyperscan	❌
ICU	✔
Glib/GRegex	✔
ECMAScript	✔

See Also

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• Capturing Groups
• Named Capturing Groups