Python：基于条件拆分，但只拆分条件的一部分

Question

我有以下字符串

random_string = '12:58 PM word \n12:20PM person \n12:39PM'

I am doing the following:
re.split(r'[\n]+\d',random_string)

And I get:
['12:58 PM word ', '2:20PM person ', '2:39PM']

But I want:
['12:58 PM word ', '12:20PM person ', '12:39PM']

你知道怎么做吗？你知道吗

Answer 1

从https://docs.python.org/2/library/re.html：

(?=...) Matches if ... matches next, but doesn’t consume any of the string. This is called a lookahead assertion. For example, Isaac (?=Asimov) will match 'Isaac ' only if it’s followed by 'Asimov'.

所以，在你的情况下：

>>> re.split(r'[\n]+(?=\d)', '12:58 PM word \n12:20PM person \n12:39PM')
['12:58 PM word ', '12:20PM person ', '12:39PM']

Answer 2

在regex中使用lookahead避免在换行后匹配数字：

>>> random_string = '12:58 PM word \n12:20PM person \n12:39PM'
>>> re.split(r'\n+(?=\d)', random_string)
['12:58 PM word ', '12:20PM person ', '12:39PM']

• 正则表达式\n+(?=\d)将在换行符上拆分，当一个数字正好位于换行符之后。你知道吗
• 无需将\n放入character类。你知道吗