正则表达式：匹配字符+换行之前（换行换行）

Question

细绳：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：HelloMy name is blah blah blahNice to meet youPS: Wait a second, I thought I know you.RegardsUnknownHang on a minuteI'm not done talkingRegardsOh OK期望的结果：My name is blah blah blahNice to meet youPS: 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)返回：\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，这错过了我认为与 [\s\S] 有关的第一个 '\n\n'。我们有什么办法可以在第一个 '\n\n' 处结束搜索？

Answer 1

重复*器是贪心的，它尽可能多地匹配直到\n\n（这是字符串中的最后一次出现）。在它后面放一个问号以使其不贪婪，以便它尽可能少地匹配：直到它匹配的第一次出现\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