I am try to write a regex to match conditional expressions, for example:
a!=2 1+2<4 f>=2+a
and I try to extract the operator. My current regex is ".+([!=<>]+).+"
But the problem is that the matcher is always trying to match the shortest string possible in the group.
For example, if the expression is a!=2, then group(1) is "=", not "!=" which is what I expect.
So how should I modify this regex to achieve my goal?
You want to match an operator surrounded by something that is not an operator.
An operator, in your definition : [!=<>]
Inversely, not an operator would be : [^!=<>]
Then try :
[^!=<>]+([!=<>]+)[^!=<>]+
You could also try the reluctant or non-greedy versions (see that other posr for extensive explain). In your example, it would be :
.+?([!=<>]+).+
But this regex could match incorrect comparisons like a <!> b, or a =!><=! b ...
Try this:
.+(!=|[=<>]+).+
your regex is matching a single ! because it is in []
Everything put in brackets will match a single char, which means [!=<>] can match: !, =, <, >
.+ that's causing the problem, as explained in another answer.
[!=<>]can represent only one character. Read about quantifiers (especially about greedy and reluctant)..+is greedy so it consumes characters which could be matched by[!=<>]+. You need to make it reluctant (or instead of.you can use negated character set to prevent matching!=<>).Reply to pshemouse@pshemo:) this way I will be notified about your comment.