Recognize regular expressions

The regular expression re in Python:

Pattern: matching patterns, following regular expression syntax

Method: matching method, search/match/split/findall/finditer/sub/subn

Introduction of re module

Re.search: search for a string and find the first string that matches

Re.match: starting with a string to match

Re.split: use regular expressions to separate strings

Re.findall: searches for matches from left to right based on regular expressions and returns a list of matching strings

Re.finditer: searches for matches from left to right based on regular expressions, returns an iterator and returns MatchObject

Re.sub: string substitution

Re.subn: like sub, returns the number of strings whose values are multiple substitutions

Re.group: returns the matching group: index 0 represents all matching strings, and index 1 starts to represent matching subgroups

Re.groupdict: returns a dictionary of named groups

Re.groups: returns matching subgroups, indexing all subgroups starting from 1

Example of operation explanation:

Re_demo (): txt=m=.search (, txt) m.groups () re_method (): s=.search (, s) .match (, s) .match (, s) re_method_2 (): s=.split (, s) re_method_3 (): s1=s2=.findall (, S1). Findall (, S2) re_method_4 (): S2 = i=.finditer ( S2) mi: m.group () re_method_5 (): S2 = .sub (, S2) .subn (, S2) re_method_6 (): data=m=.match (, data) m.group (,) m.groups () _ name__==: re_method_6 ()