First, the most commonly used matching syntax
re.match scratch match
re.search match included
re.findall all the characters into the match to return a list of elements
re.split as to match the character list separator
re.sub matching characters and replace
Second, the common regular expression notation
'.'
In addition to the default match any character other than \ n, if the specified flag DOTALL, it matches any character, including newline
'^'
Matches the beginning of the character, if the designated flags MULTILINE, which may be matched (r "^ a", " \ nabc \ neee", flags = re.MULTILINE)
'$'
End of the match character, or e.search ( "foo $", " bfoo \ nsdfsf", flags = re.MULTILINE) .group ()
'*'
Matching character * number of 0 or more times before, re.findall ( "ab *", "cabb3abcbbac") results [ 'abb', 'ab' , 'a']
'+'
Character before a match one or more times, re.findall ( "ab +", "ab + cd + abb + bba") Results [ 'ab', 'abb' ]
'?'
Matches the preceding character 1 or 0 times
'{m}'
Matches the preceding character m times
'{n,m}'
Before a matching character n to m times, re.findall ( "ab {1,3} ", "abb abc abbcbbb") Results 'abb', 'ab', 'abb']
'|'
Matching | left or | the right character, re.search. ( "Abc | ABC ", "ABCBabcCD") group () results 'ABC'
'(...)'
Packet matches, the re.search ( "(ABC) {2} A (123 | 456) C", "abcabca456c"). Group () results abcabca456c
'[]'
Character set, match all characters in brackets
'\ Z' end of the match character, the same $
'\ d' matching digits 0-9
'\ D' matches the non-digital
'\ w' animals distribution [A-Za-z0-9]
'\ W' matches non [A-Za-z0-9]
'\ s' match blank characters, \ T, \ n-, \ R & lt, the re.search ( "\ + S", "ab & \ TC1 \ N3"). Group () Results '\ t'