Re: negating words with Java regular expressions

In regular expressions
If you are looking for ";" not preceeded by a number
you could do it with the zero-width negative look
behind operators.


For your particular case, this would be.
(?![0-5]*);


This will look for numerical characters preceeding a
";", -->this is called look behind


the search will be negated "(?! )" ---> hence negative


The matching string will always only return ";" or
nothing at all. ie the pattern "[0-5]*" will never
contribute any chanracter to the resultant match-->
hence zero-width




For more info look at
http://www.regular-expressions.info/


regards
-amit shanbhag


--- Raj Ashar <Raj.Ashar@jhuapl.edu> wrote: > All, is
there a way to negate words using regular
> expressions as
> implemented by Java? I know that one can negate the
> characters in a
> character class using the caret ([^a-z]), but I
> would like to build
> expressions of the form:
>
> Match ";" and not "5;".
>
> Though one can match strings positively (as in match
> against string
> "abc"), there does not appear to be a simple way to
> indicate negative
> matches (do not match "abcd").

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