使用正则表达式获取正文，不包括特定条件

Question

I'm using Python regex to grab the body of a parsed email which may contain nothing or may look something like this:

Some coherent sentence.

lalskjfa;ljkd

the other stuff

---

A couple of lines of email signature blah blah

blah blah blah

---

I want everything in that body of the email EXCLUDING the signature line opener and its contents.

I'm basically tearing out everything but that signature email in order to reformat it for reporting.

I've tried:

• negative lookahead: \G(\A\z|.*\n*(?!_))

• positive lookahead: \G(\A\z|.*\n*(?=_))

Neither seems to be doing the trick.

With a negative lookahead, it seems to be grabbing everything. With a positive lookahead, it seems to be grabbing nothing.

The output I'm hoping to achieve is this text:

Some coherent sentence.

lalskjfa;ljkd

the other stuff

Answer 1

You may use

(?s)\A.*?(?=\n_)

It matches

• (?s) - re.DOTALL inline flag
• \A - start of string
• .*? - any 0+ chars, as few as possible till the first occurrence of
• (?=\n_) - a newline followed with _ char.