Question

I’m a Python-regex newbie, so bear with me…

I have a long, multiline string, in which I have to replace the directory parts of [[…]] strings with other stuff, but ONLY IF they do not start with ‘file://’, so e.g.

    s= 'chk1 [[file:///excursions/digital/MindMaps/|mm]],
    local file [[file:///inFolder/tmptest/a/fan.txt|a/fan.txt]]
    and nonlocal [[/excursions/books/calsync.txt|/excursions/books]]'

I used variations of this (at the moment the replace string is just a check of what I found):

re.sub('\[\[(?!file:)(^])*',"found:< \\1 >",s)

but I get a “sre_constants.error: unmatched group”. Do you know what I’m doing wrong?

thanks!

alessandro

Answer 1

You’re missing the [] operator in the second group:

'\[\[(?!file:)(^])*

should be

'\[\[(?!file:)([^\]]*)'

It’s also better to use raw strings when you have a lot of escaping:

re.sub(r'\[\[(?!file:)([^\]]*)', r"found:<\1>", s)