'     999' or
'   9999' or
'9999999'
'      9'.
[download]

Is "field" length 7 or 8 chars? What is a "field" (part of a larger string)?

but when you're checking a 16 byte filed ZZZZZZZZZZZZ9V99

Um, there is no description of what you want for that one :) one thing at a time?

whilst doing the job,is getting ludicrously large and unreadable

Instead of one regex, write twelve thirteen??

Stop writing unreadable regex :) Write beautiful regex, not ugly, so you can read :) How can I hope to use regular expressions without creating illegible and unmaintainable code?

Someone at work suggested using an sprintf in it's stead within the regex, but I must be honest and say that suggestion has left me clueless on how to do it.

Are you trying to format a string? If you are, go ahead and use sprintf, otherwise ...

write a function?

Hope this helps