Can you use the number of matched characters later in the regex?

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August 26th, 2011, 06:01 PM

fishtoprecords

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Can you use the number of matched characters later in the regex?

I'm using Java's regex engine. I've got data that matches:

Quote:

(\\d{8}+|\\p{Upper}{2}\\d{6}+|\\p{Upper}\\d{7}+)

What it really means is any of:
eight digits
or two letters and six digits
or one letter and seven digits.

It would be cool if I could have some sort of backreference to the number of characters matched in the pattern so I could use something like

Quote:

\\p{Upper}{0,2}\\d{8-n}+

Is this possible?
Thanks
Pat

August 26th, 2011, 06:47 PM

requinix

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Not really, but if you can have

Code:

(?=[\d\p{Upper}]{8})(\p{Upper}{0,2}\d{6,8})

That's normally more complicated than I go - I typically go the same kind of alternation route you did:

Code:

(dd|U(d|U))d{6}
(dd|Ud|UU)d{6}
d{8}|Ud{7}|UUd{6}

(Basically, I start with the first and unravel as I feel like it.)

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