Re: regex help wanted

On Thu, Apr 25, 2013 at 10:32:26AM -0400, Tom Lane wrote:

> Karsten Hilbert <Karsten(dot)Hilbert(at)gmx(dot)net> writes:
> > What I don't understand is: Why does the following return a
> > substring ?
>
> > select substring ('junk $<allergy::test::99>$ junk' from '\$<[^<]+?::[^:]+?>\$');
>
> There's a perfectly valid match in which [^<]+? matches allergy::test
> and [^:]+? matches 99.

Tom, thanks for helping !

I would have thought "<[^<]+?:" should mean:

match a "<"
followed by 1-n characters as long as they are not "<"
until the VERY NEXT ":"

The "?" should make the "+" after "[^<]" non-greedy and thus
stop at the first occurrence of ":", right ? Or am I
misunderstanding that part ?

At any rate,

select substring ('junk $<allergy::test::99>$ junk' from '\$<[^<:]+?::[^:]+?>\$');

(which follows from your hint) appears to do what I need.

Thanks,
Karsten
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