什么是正则表达式？

Question

我使用Nltk的punkt标记器将一个段落标记为句子，但是在下面的例子中，标记器无法识别句子，因为句点后面跟着数字。我想使用正则表达式来识别这些场景，并用'.1,7,9'替换'. 1,7,9'，即在引用和句点之间添加空格。你知道吗

Ex1.  `This is a random sentence.1,7,9 This is a sentence followed by it.`
Ex2. I love football.1,7,24`I also like cricket.

Ex3. ESD for undifferentiated  cancers.[1][7]`Cancers can be treatable.

预期产量：

EX1. This is a random sentence.
     1,7,9 This is a sentence followed by it.
Ex2. I love football.
     ESD for undifferentiated  cancers.1,7
Ex3. ESD for undifferentiated  cancers.1,7
     [1][7]`Cancers can be treatable.

谢谢你。你知道吗

Answer 1

下面的正则表达式将用.+\n替换后跟非空格字符的所有点

>>> import re
>>> s = "Ex1.  This is a random sentence.1,7,9 This is a sentence followed by it."
>>> print(re.sub(r'\.(\S)', r'.\n\1', s))
Ex1.  This is a random sentence.
1,7,9 This is a sentence followed by it.

DEMO

Answer 2

在附加的整数列表是引用的情况下，将字符return放在整数列表之后可能很有用：

>>> import re
>>> s = "Ex1.  This is a random sentence.1,7,9 This is a sentence followed by it."
>>> print(re.sub(r'(\.\S+\s)', r'\1\n', s))
Ex1.  This is a random sentence.1,7,9 
This is a sentence followed by it.