多行图案和标签搜索

Question

I'm trying to make a pattern for tags, but the sub method just replaces the first char and 3 at the end of the line, im trying to replace all tags on the line and with multiline

p=re.compile('<img=([^}]*)>([^}]*)</img>', re.S)
p.sub(r'[img=\1]\2[/img]','<img="test">dsad</img> <img="test2">dsad2</img>')
output:
'**[**img="test">dsad</img> <img="test2"]dsad2**[/img]**'

Answer 1

You're using towards the start of your re's pattern:

<img=([^}]*)>

this will gobble up (as group 1) all characters after the leading <img= , including other tags!!! , up to the last > it can possibly gobble; * is GREEDY -- it gobbles up as much as it possibly can. Not sure why you're specifically excluding closed-braces } ? Maybe you meant to exclude closed angular brackets instead ( > ).

For NON-greedy matching, instead of * , you need *? ; with that, you'll be gobbling up as little as you can, instead of as much as you can. So, I think you mean:

p = re.compile(r'<img=([^>]*?)>(.*?)</img>', re.S)

this matches one img tag (and all tags inside it), and appears to be performing exactly the substitutions you mean.