python re match strings not ending with word

Question

I'm trying to match all strings not ending with a specific word. For some reason the following doesn't work:

>> import re
>> my_str = 'static/assets/img/favicon.ico'
>> re.search('^static.+(?!ico)$', my_str)
<_sre.SRE_Match at 0x7f08b9773440>

Can you please explain why it's not working and how to fix it?

Answer 1

I think you want to use a negative lookbehind, not lookahead.

^static.+$(?<!ico)

See demo at regex101 if this is what you needed.

---

(?!ico)$ or $(?!ico) would look if there is not ico after the end which is impossible.

Answer 2

You should use:

print re.search(r'^(?!.*ico$)static.+', my_str)
None

(?!.*ico$) asserts that string doesn't end with ico