CheatSheet for Regular Expression

Metacharacters Defined MChar Definition ^ Start of a string. $ End of a string. . Any character (except \n newline) | Alternation. {...} Explicit quantifier notation. [...] Explicit set of characters to match. (...) Logical grouping of part of an expression. * 0 or more of previous expression. + 1 or more of previous expression. ? 0 or 1 of previous expression; also forces minimal matching when an expression might match several strings within a search string. \ Preceding one of the above, it makes it a literal instead of a special character. Preceding a special matching character, see below.

Metacharacter Examples Pattern Sample Matches ^abc abc, abcdefg, abc123, ... abc$ abc, endsinabc, 123abc, ... a.c abc, aac, acc, adc, aec, ... bill|ted ted, bill ab{2}c abbc a[bB]c abc, aBc (abc){2} abcabc ab*c ac, abc, abbc, abbbc, ... ab+c abc, abbc, abbbc, ... ab?c ac, abc a\sc a c

Escaped Char	Description
ordinary characters	Characters other than . $ ^ { [ ( | ) ] } * + ? \ match themselves.
\a	Matches a bell (alarm) \u0007.
\b	Matches a backspace \u0008 if in a []; otherwise matches a word boundary (between \w and \W characters).
\t	Matches a tab \u0009.
\r	Matches a carriage return \u000D.
\v	Matches a vertical tab \u000B.
\f	Matches a form feed \u000C.
\n	Matches a new line \u000A.
\e	Matches an escape \u001B.
\040	Matches an ASCII character as octal (up to three digits); numbers with no leading zero are backreferences if they have only one digit or if they correspond to a capturing group number. (For more information, see Backreferences.) For example, the character \040 represents a space.
\x20	Matches an ASCII character using hexadecimal representation (exactly two digits).
\cC	Matches an ASCII control character; for example \cC is control-C.
\u0020	Matches a Unicode character using a hexadecimal representation (exactly four digits).
\*	When followed by a character that is not recognized as an escaped character, matches that character. For example, \* is the same as \x2A.

Char Class	Description
.	Matches any character except \n. If modified by the Singleline option, a period character matches any character. For more information, see Regular Expression Options.
[aeiou]	Matches any single character included in the specified set of characters.
[^aeiou]	Matches any single character not in the specified set of characters.
[0-9a-fA-F]	Use of a hyphen (–) allows specification of contiguous character ranges.
\p{name}	Matches any character in the named character class specified by {name}. Supported names are Unicode groups and block ranges. For example, Ll, Nd, Z, IsGreek, IsBoxDrawing.
\P{name}	Matches text not included in groups and block ranges specified in {name}.
\w	Matches any word character. Equivalent to the Unicode character categories [\p{Ll}\p{Lu}\p{Lt}\p{Lo}\p{Nd}\p{Pc}]. If ECMAScript-compliant behavior is specified with the ECMAScript option, \w is equivalent to [a-zA-Z_0-9].
\W	Matches any nonword character. Equivalent to the Unicode categories [^\p{Ll}\p{Lu}\p{Lt}\p{Lo}\p{Nd}\p{Pc}]. If ECMAScript-compliant behavior is specified with the ECMAScript option, \W is equivalent to [^a-zA-Z_0-9].
\s	Matches any white-space character. Equivalent to the Unicode character categories [\f\n\r\t\v\x85\p{Z}]. If ECMAScript-compliant behavior is specified with the ECMAScript option, \s is equivalent to [ \f\n\r\t\v].
\S	Matches any non-white-space character. Equivalent to the Unicode character categories [^\f\n\r\t\v\x85\p{Z}]. If ECMAScript-compliant behavior is specified with the ECMAScript option, \S is equivalent to [^ \f\n\r\t\v].
\d	Matches any decimal digit. Equivalent to \p{Nd} for Unicode and [0-9] for non-Unicode, ECMAScript behavior.
\D	Matches any nondigit. Equivalent to \P{Nd} for Unicode and [^0-9] for non-Unicode, ECMAScript behavior.