正则表达式中最常见的符号和字符

Notation	Description	Example RE
Symbols
literal	Match literal string valueliteral	foo
re1|re2	Match regular expressionsre1 or re2	foo|bar
.	Matchany character (except NEWLINE)	b.b
^	Match start of string	^Dear
$	Match end of string	/bin/*sh$
*	Match 0 or more occurrences of preceding RE	[A-Za-z0-9]*
+	Match 1 or more occurrences of preceding RE	[a-z]+\.com
?	Match 0 or 1 occurrence(s) of preceding RE	goo?
{N}	Match N occurrences of preceding RE	[0-9]{3}
{M,N}	Match from M to N occurrences of preceding RE	[0-9]{5,9}
[...]	Match any single character fromcharacter class	[aeiou]
[..x-y..]	Match any single character in therange fromx to y	[0-9],[A-Za-z]
[^...]	Do not match any character from character class, including any ranges, if present	[^aeiou], [^A-Za-z0-9_]
(*|+|?| {})?	Apply "non-greedy" versions of above occurrence/repetition symbols (*,+, ?, {})	.*?[a-z]
(...)	Match enclosed RE and save assubgroup	([0-9]{3})?, f(oo|u)bar
Special Characters
\d	Match any decimal digit, same as [0-9](\D is inverse of \d: do not match any numeric digit)	data\d+.txt
\w	Match any alphanumeric character, same as [A-Za-z0-9_] (\W is inverse of\w)	[A-Za-z_]\w+
\s	Match any whitespace character, same as [ \n\t\r\v\f] (\S is inverse of\s)	of\sthe
\b	Match any word boundary (\B is inverse of \b)	\bThe\b
\nn	Match saved subgroup nn (see (...) above)	price: \16
\c	Match any special character c verbatim (i.e., with out its special meaning, literal)	\., \\, \*
\A (\Z)	Matchstart (end) of string (also see ^ and $ above)	\ADear

REF:Core Python Programming