Disable "group becomes tuple" behavior of Python's re.findall()

Question

When I use a regex in Python 2.x containing two or more groups, re.findall() returns a list of n-tuples for the n groups contained by the regex. I know it's supposed to work like this but is there any way to circumvent this behavior?

For instance, when I run

import re
sentence = 'We also learned that the !!probability of an outcome is its relative frequency over endless repetitions of the experiment. '
print re.findall(r'[Pp]robabilit(y|ies)',sentence)

它只返回['y']。但是，我想probability返回。对于包含“概率”的其他句子，我想probabilities返回，依此类推。

Answer 1

re.findall存在一个或多个组时更改的行为。它返回一个组列表；如果有多个组，则列出一个元组。

通过将该组设置为非捕获组，可以得到所需的内容：

>>> re.findall(r'[Pp]robabilit(?:y|ies)',sentence)
['probability']

或者使用re.finditer和列表理解：

>>> [m.group() for m in re.finditer(r'[Pp]robabilit(y|ies)',sentence)]
['probability']