如何在python中获得regex match的一部分作为变量?

参见: Python regex match objects

>>> import re
>>> p = re.compile("lalala(I want this part)lalala")
>>> p.match("lalalaI want this partlalala").group(1)
'I want this part'

如果要按名称获取部件,也可以执行以下操作:

>>> m = re.match(r"(?P<first_name>\w+) (?P<last_name>\w+)", "Malcom Reynolds")
>>> m.groupdict()
{'first_name': 'Malcom', 'last_name': 'Reynolds'}

这个例子取自 re docs

import re
astr = 'lalalabeeplalala'
match = re.search('lalala(.*)lalala', astr)
whatIWant = match.group(1) if match else None
print(whatIWant)

小提示:在Perl中,当您编写

$string =~ m/lalala(.*)lalala/;

regexp可以匹配字符串中的任何位置。等价物是用 re.search() 函数,而不是 re.match() 函数,它要求模式匹配从字符串的开头开始。

import re
data = "some input data"
m = re.search("some (input) data", data)
if m: # "if match was successful" / "if matched"
  print m.group(1)

检查 docs 更多。

不需要regex。想想简单。

>>> "lalala(I want this part)lalala".split("lalala")
['', '(I want this part)', '']
>>> "lalala(I want this part)lalala".split("lalala")[1]
'(I want this part)'
>>>

import re
match = re.match('lalala(I want this part)lalala', 'lalalaI want this partlalala')
print match.group(1)

import re

string_to_check = "other_text...lalalaI want this partlalala...other_text"

p = re.compile("lalala(I want this part)lalala")    # regex pattern
m = p.search(string_to_check)                       # use p.match if what you want is always at beginning of string

if m:
    print m.group(1)

在尝试将Perl程序转换为用模块解析函数名的Python时,我遇到了这个问题,我收到一个错误,说“group”未定义。我很快意识到这个例外是因为P。 比赛 /P. 搜索 如果没有匹配的字符串,则返回0。

因此,Group运算符不能对其执行操作。因此,为了避免出现异常,请检查是否存储了匹配项,然后应用group运算符。

import re

filename = './file_to_parse.py'

p = re.compile('def (\w*)')            # \w* greedily matches [a-zA-Z0-9_] character set


for each_line in open(filename,'r'):
    m = p.match(each_line)             # tries to match regex rule in p
    if m:
        m = m.group(1)
        print m