将Perl正则表达式转换为Python正则表达式

时间:2011-01-23 22:45:47

标签: python regex perl

我在将Perl正则表达式转换为Python时遇到了问题。我想要匹配的文字有以下模式:

Author(s)    : Firstname Lastname  
               Firstname Lastname  
               Firstname Lastname  
               Firstname Lastname

在perl中我能够匹配这个并用

提取作者
/Author\(s\)    :((.+\n)+?)/

当我尝试

re.compile(r'Author\(s\)    :((.+\n)+?)')

在Python中,它与第一个作者匹配两次并忽略其余部分。

有谁能解释我在这里做错了什么?

3 个答案:

答案 0 :(得分:3)

您可以这样做:

# find lines with authors
import re

# multiline string to simulate possible input
text = '''
Stuff before
This won't be matched...
Author(s)    : Firstname Lastname  
               Firstname Lastname  
               Firstname Lastname  
               Firstname Lastname
Other(s)     : Something else we won't match
               More shenanigans....
Only the author names will be matched.
'''

# run the regex to pull author lines from the sample input
authors = re.search(r'Author\(s\)\s*:\s*(.*?)^[^\s]', text, re.DOTALL | re.MULTILINE).group(1)

上面的正则表达式匹配起始文本(作者,空格,冒号,空格),它通过匹配后面以空格开头的所有行来提供下面的结果:

'''Firstname Lastname  
           Firstname Lastname  
           Firstname Lastname  
           Firstname Lastname
'''

然后,您可以使用以下正则表达式对这些结果中的所有作者进行分组

# grab authors from the lines
import re
authors = '''Firstname Lastname  
           Firstname Lastname  
           Firstname Lastname  
           Firstname Lastname
'''

# run the regex to pull a list of individual authors from the author lines
authors = re.findall(r'^\s*(.+?)\s*$', authors, re.MULTILINE)

其中列出了作者名单:

['Firstname Lastname', 'Firstname Lastname', 'Firstname Lastname', 'Firstname Lastname']

组合示例代码:

text = '''
Stuff before
This won't be matched...
Author(s)    : Firstname Lastname  
               Firstname Lastname  
               Firstname Lastname  
               Firstname Lastname
Other(s)     : Something else we won't match
               More shenanigans....
Only the author names will be matched.
'''

import re
stage1 = re.compile(r'Author\(s\)\s*:\s*(.*?)^[^\s]', re.DOTALL | re.MULTILINE)
stage2 = re.compile('^\s*(.+?)\s*$', re.MULTILINE)

preliminary = stage1.search(text).group(1)
authors = stage2.findall(preliminary)

将作者设置为:

['Firstname Lastname', 'Firstname Lastname', 'Firstname Lastname', 'Firstname Lastname']

成功!

答案 1 :(得分:2)

一组只能匹配一次。因此,即使您的匹配组重复,您也只能访问上一次实际匹配。您必须一次匹配所有名称然后将它们拆分(通过换行或甚至新的正则表达式)。

答案 2 :(得分:1)

尝试

re.compile(r'Author\(s\)    :((.+\n)+)')

在原始表达式中,+?表示您希望匹配非贪婪,即最小。