Regular Expression Quick Reference

Anchors

^

Start of string, or start of line in multiline mode.

$

End of string, or end of line in multiline mode.

\b

Word boundary between a word and a non word character.

\B

Position that is not a word boundary.

Quantifiers

*

Zero or more of the preceding element.

+

One or more of the preceding element.

?

Zero or one of the preceding element.

{n,m}

Between n and m repetitions, both bounds optional.

*? +? ??

Lazy variants, match as few characters as possible.

Groups

(...)

Capturing group, numbered from left to right.

(?:...)

Non capturing group.

(?<name>...)

Named capturing group.

(?=...)

Positive lookahead, zero width.

(?!...)

Negative lookahead, zero width.