Simple regex question - match parameter in URL

[Warren]

Sorry to ask something so elementary, but I'm just not getting it.

suppose I want to match the value of parameter b from a URL like
http://www.abcd.com/?a=1&b=2&c=3

I can use this regex expression:
&b=(.+)&

and then pull the value of group 1.

But suppose the c parameter is not included - the URL is
http://www.abcd.com/?a=1&b=2

Then, of course, the & doesn't match. So I have to replace it with
either nothing, or \b, or \Z, or something equivalent. They all work.

What I *don't* get is how to OR those conditions together. If the
second condition were a character, then I could create a character
class. But even though "&b=(.+)\Z" works, "&b=(.+)[\Z]" does not.

I know there's something simple here I'm not quite getting. Can some
provide a clue? Thanks.

 

[Ethan Strauss]

I am pretty sure that
&b=(.+)&?
will work.
The question mark means zero or one match

Ethan

 

[Kevin Spencer]

The following will capture ALL parameters in a QueryString, placing the name
into a group named "name" and the value into a group named "value":

[\?&](?<name>[^&=]+)=(?<value>[^&=]+)

--
HTH,

Kevin Spencer
Microsoft MVP

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