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Posted by Curt Zirzow on 11/16/05 07:00
On Tue, Nov 15, 2005 at 10:39:19PM -0500, Leonard Burton wrote:
> HI Curt,
>
> Thanks for the reply,
>
> > What does a amateur radio callsign look like? And in what context
> > are you trying to parse this callsign?
>
> Basically here is the regex I used (I am not the best with regexes):
>
> $pattern = "/^[0-9]?[A-Z]{1,2}[0-9][A-Z]{1,3}/";
>
> Here are how they look
> W1W
> W1AW
> WA1W
> AD4HZ
> N9URK
> WB6NOA
> 4N1UBG
Ok, so i can conclude so far we have alpha numeric chars minimum of
3 chars up to 6, this would make a regex:
/[A-Z0-9]{3,6}/
I would assume however that the first char (or two) probably
signifies the location of the callsign and based on the location a
certain pattern is needed.
>
> I guess this would be better?
>
> $pattern = "/^";
> $pattern .= "([0-9][A-Z][0-9][A-Z]{3})|"; //4N1UBG
> $pattern .= "([A-Z][0-9][A-Z]{1,3})|"; //N9URK, W1AW, W1W
> $pattern .= "([A-Z]{2}[0-9][A-Z]{1,3})"; //WB6NOA, AD4HZ, WA1W
> $pattern .= "/";
>
> I am still trying to master regexes. Is there a better way to do this?
For one trying to master regex's you seem to have a good grasp on
it. If this pattern works according to the specs of a callsign, it
should work fine. You could try to combine the regex into one
statment (without the | condition) but that would make the regex
rather ugly.
One thing i would suggest, although probably a minor issue
considering how long the string is, is to make sure you put the
most likely match in your first pattern to match.
Curt.
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