In Vim, is there a way to search for lines that match say abc
but do not also contain xyz
later on the line? So the following lines would match:
Your attempt was pretty close; you need to pull the .*
that allows an arbitrary distance between the match and the asserted later non-match into the negative look-ahead:
/abc\(.*xyz\)\@!
I guess this works because the non-match is attempted for all possible matches of .*
, and only when all branches have been exhausted is the \@!
declared as fulfilled.
I think I'd write this as /abc\(\(xyz\)\@!.\)*$
I'm not sure whether this is faster than other suggestions (I think it might be since it tests each position only once) but it makes conceptual sense as:
"abc followed by anything which is not xyz, any number of times until end of line"
I like that better than "abc followed by anything not followed by xyz" as in the other patterns mentioned.
I always find it weird, that you need to escape brackets in vim, so I try to use the "very magic" mode most of the time, activated with \v
:
/\vabc(.*xyz)@!
This works for me /abc\(.*xyz\)\@!
Although your question is about lookahead, I found it while searching for lookbehind. Thus, I post the solution to lookbehind so that others may find it.
If you search for pattern2
not preceded by pattern1
, that is negative lookbehind, search for:
\(pattern1\)\@<!pattern2