Regular Expressions Cheat Sheet
A regular expression specifies a set of strings that matches it. This cheat sheet is based off Python 3’s Regular Expressions (http://docs.python.org/3/library/re.html) but is designed for searches within Sublime Text.
Special Characters \ Escapes special characters or signals a special sequence. . Matches any single character except a newline. ^ Matches the start of the string. $ Matches the end of the string. * Greedily matches 0 or more repetitions of the preceding RE. *? Matches 0 or more repetitions of the preceding RE. + Greedily matches 1 or more repetitions of the preceding RE. +? Matches 1 or more repetitions of the preceding RE. ? Greedily matches 0 or 1 repetitions of the preceding RE. ?? Matches 0 or 1 repetitions of the preceding RE. A|B Matches A, if A is unmatched then matches B, where A and B are arbitrary REs. {m} Matches exactly m many repetitions of the previous RE. {m,n} Greedily matches from m many to n many repetitions of the previous RE. {m,n}? Matches m many to n many repetitions of the previous RE.
[…] Indicates a set of characters to match. [amk] Matches ‘a’, ‘m’, or ‘k’. [a-z] Matches ‘a’ through ‘z’. [a-f0-7] Matches ‘a’ through ‘f’ or ‘0’ through ‘7’. [a-z] Matches ‘a’, ‘-‘, or ‘z’. [a-] Matches ‘a’ or ‘-‘. [-a] Matches ‘a’ or ‘-‘. [(+*)] Matches ‘(‘, ‘+’, ‘*’, or ‘)’. [] matches special characters literally. [\w] Matches the character class for ‘\w’. See character classes. [^5] Matches anything other than ‘5’. ‘^’ forms the complementary set only as the first character in a set. ] Matches ‘]’, ‘(‘, and ‘)’. ‘]’ is taken literally only as the first character in a set. [()]] Matches ‘]’, ‘(‘, and ‘)’.
(…) Matches the RE inside the parenthesis and assigns a new group.
(?P
(?…) Extension notation which changes a RE’s behavior. These do not assign a new group. (?aiLmsux) Sets the corresponding flag to each letter. Does not work within Sublime Text. (?:…) A non-capturing version of parenthesis. The matched substring cannot be retrieved later. (?P=name) Matches the substring matched by the group named name. (?#…) A comment, the contents are ignored. (?=…) Lookahead assertion, the preceding RE only matches if this matches. (?!…) Negative look ahead assestion, the preceding RE only matches if this doesn’t match. (?<=…) Positive look behind assertion, the following RE will only match if preceeded with this fixed length RE. (?<!…) Negative look behind assertion, the following RE will only match if not preceeded with this fixed length RE. (?(id)true|false) If group id exists then uses the true RE, else use the false RE.
Character classes \1 Matches the contents of the group labelled by the same number. Acceptable numbers are 1-99. \A Matches at the start of the current string. \b Matches the empty string at the beginning or end of a word. \b matches the boundary between \w and \W. \B Matches the empty string not at the beginning or end of a word. \d Matches any Unicode decimal digit, including 0-9. \D Matches any Unicode non-decimal digit. \s Matches any Unicode whitespace character, including ‘ ‘, \t, \n, \r, \f and \v. \S Matches any Unicode non-whitespace character. \w Matches any Unicode word character, including a-z, A-Z, and 0-9. \W Matches any Unicode non-word character. \Z Matches at the end of the string.
\a Matches the ASCII Bell (). \f Matches the ASCII Formfeed ( ). \n Matches the ASCII Linefeed. \r Matches the ASCII Carriage Return ( ). \t Matches the ASCII Horizontal Tab. \v Matches the ASCII Vertical Tab ( ).