正则表达式：匹配字符+换行之前（换行换行）

Question

字符串：

testing = "\nHello\nMy name is blah blah blah\nNice to meet you\nPS: Wait a second, I thought I know you.\nRegards\n\nUnknown\n\nHang on a minute\nI'm not done talking\n\nRegards\nOh OK"

打印：

Hello
My name is blah blah blah
Nice to meet you
PS: Wait a second, I thought I know you.
Regards

Unknown

Hang on a minute
I'm not done talking

Regards
Oh OK

期望的结果：

My name is blah blah blah
Nice to meet you
PS: Wait a second, I thought I know you.
Regards

尝试的解决方案：

test = re.search('(Hello)([\s\S]*)(\n\n)', testing).group(2)

哪个returns:

\nMy name is blah blah blah\nNice to meet you\nPS: Wait a second, I thought I know you.\nRegards\n\nUnknown\n\nHang on a minute\nI'm not done talking

但是，这错过了第一个“\n\n”，我认为它与 [\s\S] 有关。有什么方法可以在第一个“\n\n”结束搜索？

谢谢！

Answer 1

* 重复器是 greedy，它尽可能匹配直到 \n\n （这是字符串中的最后一次出现）。在它后面打一个问号，让它成为 non-greedy 所以它匹配的越少越好：直到它第一次出现匹配 \n\n:

test = re.search('(Hello)([\s\S]*?)(\n\n)', testing).group(2)
print(test)

输出：

Hello
My name is blah blah blah
Nice to meet you
PS: Wait a second, I thought I know you.
Regards

正则表达式：匹配字符+换行之前（换行换行）

Regex: Match char + new line before (new line new line)

python

python-re