正则表达式多行替换

Question

So I have this:

z='===hello  
there===,  
how are ===you===?'

And I want to be:

z='<b>hello  
there<\b>,  
how are <b>you<\b>?'

I tried doing this:

z = re.sub(r"\={3}([^\$]+)\={3}", r"<b> \\1 </b>", z, re.M)  

And it works sort of but I got this instead:

z='<b>hello  
there===,  
how are ===you<\b>?'  

I'm still new to this but I believe it's the ^ and $ that makes it match the beginning and the end of the string. So how do I change it so it matches the ones in the middle?

Answer 1

re.sub(r"\={3}([^\$]+?)\={3}", r"<b> \\1 </b>", z, re.M)

从python doc复制单击此处 ：

*?, +?, ?? The '*', '+', and '?' qualifiers are all greedy; they match as much text as possible. Sometimes this behaviour isn't desired; if the RE <.*> is matched against '<H1>title</H1>', it will match the entire string, and not just '<H1>'. Adding '?' after the qualifier makes it perform the match in non-greedy or minimal fashion; as few characters as possible will be matched. Using .*? in the previous expression will match only '<H1>'.