Python Group ()

In a regular expression, group () is used to present a string that is intercepted by a packet , () to group

Import rea = "123abc456" Print Re.search ("([0-9]*) ([a-z]*] ([0-9]*)", a). Group (0)   #123abc456, return to overall print re.search (" ([0-9]*) ([a-z]*) ([0-9]*) ", a). Group (1)   #123print re.search (" ([0-9]*) ([a-z]*] ([0-9]*) ", a). Group (2)   #abcprint re.search (" ([ 0-9]*) ([a-z]*) ([0-9]*) ", a). Group (3)   #456

The reason

1. Three sets of parentheses in regular expressions divide matching results into three groups

• Group () with group (0) is the overall result of matching regular expressions
• Group (1) lists the first bracket matching section, Group (2) lists the second bracket matching part, and group (3) lists the third bracket matching part.

2. No match succeeded, Re.search () return None

3. There is certainly no parenthesis in the Zheng expression, and group (1) must be wrong.

=eg:=================================

#! /usr/bin/python
#-*-Coding:utf-8-*-
Import re
Zhpattern = re.compile (U ' [\u4e00-\u9fa5]+ ')
#判断一段文本中是否包含简体中:
Contents=u ' to determine if a text contains Simplified Chinese: yes, it's not.
Match = Zhpattern.search (contents)

If match:
Print (U ' with Chinese:%s '% (Match.group (0),))
Else
Print (U ' does not contain Chinese ')

Python Group ()