如何使用 python 中的正则表达式匹配两个单词之间包含新行的所有字符？

Question

for example I have something like:

OLD

WHO IS THIS

END?

On Sun, 22 Sep 2019 at 23:57,

I'd like to capture everything from the beginning till \n\nOn Sun,
so my expected outcome would be:

OLD

WHO IS THIS

END?

I tried doing the following pattern: ^(.*)\n\nOn.* wrote: which only works if the text I need doesn't contain new lines. I'd really appreciate any help. Thanks.

Answer 1

No need for Regex try this:

text = """
OLD

WHO IS THIS

END?

On Sun, 22 Sep 2019 at 23:57,
"""

text = '\n'.join(line for line in text.split('\n') if line.startswith('On Sun'))
print(text)

Output:

OLD

WHO IS THIS

END?

Answer 2

The direct translation would be

^OLD.+?(?=^On Sun)

See a demo on regex101.com (mind the multi- and singleline flags).