有条件地删除两个换行符的正则表达式

Question

我正在尝试删除文本文件中每行末尾的两个换行符，但前提是它遵循小写字母，即 [a-z]。 我有以下代码：

import re
text = "I want this \n\nwith one line break \n\nIn this place \nNothing happens \n\nHere\nnothing should\nhappen too."
texts = re.sub(r"(?<=[a-z])\r?\n\n"," ", text)
print(texts)

我要获取的文字

text = "I want this \nwith one line break \n\nIn this place \nNothing happens \n\nHere\nnothing should\nhappen too."

在我的代码中，文本没有任何变化。我的代码遵循这个已回答的问题：Regular expression to remove line breaks，但我无法使其适应两个换行符。

Answer 1

看来你需要一个积极的前瞻，而不是后瞻，在之后有一个小写字符

import re

expected = "I want this \nwith one line break \n\nIn this place \nNothing happens \n\nHere\nnothing should\nhappen too."
text     = "I want this \n\nwith one line break \n\nIn this place \nNothing happens \n\nHere\nnothing should\nhappen too."
texts = re.sub(r"\n\n(?=[a-z])", "\n", text)

print(texts == expected)