Rustexp

Regex

Subject Use fancy-regex.

Reference

. non-newline char
^ start of line
$ end of line
\b word boundary
\B non-word boundary
\A start of subject
\z end of subject
\d decimal digit
\D non-decimal digit
\s whitespace
\S non-whitespace
\w word character
\W non-word character
(a|z) a or z
[az] a or z
[^az] not a or z
[a-z] a through z
(foo) capture foo
a? 0 or 1 a
a* 0 or more a
a+ 1 or more a
a{3} 3 of a
a{3,} 3 or more a
a{3,5} 3 through 5 a

Modifiers (enable: (?a), disable: (?-a))

u unicode
i case insensitive
s dot matches newline
m multiline
x whitespace ignored

For more information see the documentation for the regex crate .

Additional escapes

\h hex digit ([0-9A-Fa-f])
\H not hex digit ([^0-9A-Fa-f])
\e escape control character
\K keep text out of match
\G anchor to previous match
\Z anchor to the end of the text before any trailing newlines
\O any character including newline

Capture groups and backreferences

\1 match first capture group
\2 match second capture group
\{N} match Nth capture group
(?<name> exp) capture group named name
\k<name> match capture group name

Lookaround

(?=exp) look-head for exp
(?!exp) negative look-head for exp
(?<=exp) look-behind for exp
(?<!exp) negative look-behind for exp

Atomic groups

(?>exp) no backtracking in exp

Conditions

(?(1)) continue if first capture group matched
(?(<name>)) continue if capture group name matched
(?(1)true|false) if the first capture group matched then execute the true regex expression, else execute false
(?(condition)true|false) if the condition matches then execute the true regex expression, else execute false

For more information see the documentation for the fancy-regex crate .