Python Learning 4 Regular expressions

Symbol	Description	Example
Literal	Match the value of a string	Foo
Re1|re2	Match regular expression Re1 or Re2	Foo|bar
.	Match any character (except line breaks)	B.b
^	Match the start of a string	^dear
$	Match the end of a string	/bin/*sh$
*	Matches the preceding occurrence of the regular expression 0 or more times	[a-za-z0-9]*
+	Matches the preceding occurrence of the regular expression 1 or more times	[a-z]+\.com
?	Matches the preceding occurrence of the regular expression 0 or more times	Goo?
N	Matches the preceding occurrence of the regular expression n times	[0-9] {3}
{M,n}	Matches regular expressions that recur m-n times	[0-9] {5,9}
[...]	Match any one of the characters that appear in the character set	[Aeiou]
[.. X-y:]	Match any character from character X to Y	[0-9],[a-za-z]
[^...]	does not match any one of the characters that appear in this character set, Include a range of characters	[^a-za-z0-9_]
(*|+|?| {})	For any "non-greedy" version that appears above Repeat match number symbol (*,+,?,{})	.*? [A-z]
(...)	Match enclosing parentheses in a regular expression (RE), and keep it as a child group	([0-9]{3})?, f (oo|u) bar
Special symbols
\d	Match any number, and [0-9] (\d is the inverse of \d: any non-number symbol)	Data\d+.txt
\w	Match any numeric alphabetic character (\w is the \w)	[a-za-z_]\w+
\s	Matches any whitespace character, and [\n\t\r\v\f] (\s is the \s)	Of\sthe
\b	Match word boundaries (\b is the \b)	\bthe\b
\nn	Match a saved child group	Price: \16
\c	Match the special character C individually	\.,\\,\*
\a (\z)	Start of Match string (end)	\adear
Common regular expression functions and methods
Compile (pattern,flags=0)	Compiles the regular expression pattern and returns a Regex object
Match (Pattern,string,flags=0)	Match the string with the regular expression pattern, Match successfully returns the Match object, otherwise none is returned
Search (pattern,string,flags=0)	Matches the first occurrence of a string with a regular expression pattern, Match successfully returns the Match object, otherwise none is returned
FindAll (Pattern,string[,flags])	Finds all (non-repeating) occurrences of the regular expression pattern in string strings, Returns a list of matching objects
Finditer (Pattern,string[,flags])	Searches for a string, returning an iterator that sequentially accesses each match result (Match object)
Split (pattern,string,max=0)	Returns a list after the string is split in pattern mode. Max is used to specify the maximum number of splits and does not specify that all will be split.
Sub (pattern,rep1,string,max=0)	Returns the replaced string after using REPL to replace each substring of a string that matches the pattern.
Group (num=0)	Return all matching objects
Groups ()	Returns a tuple that contains all of the matched child tuples

Examples of greedy and non-greedy matching:

1 ImportRe2 3Data='Thu Nov 01:14:11 2001::[email protected]::6777874277-5-8'4 5 6 #non-greedy match7patt4='.+? (\d+-\d+-\d+)'8m=Re.match (PATT4, data)9 Print(M.group (1))Ten  One #Greedy Match A  -patt5='. + (\d+-\d+-\d+)' -m=Re.match (PATT5, data) the Print(M.group (1))

Output Result:

6777874277-5-87-5-8

Python Learning 4 Regular expressions