http://www.perlmonks.org?node_id=963816


in reply to Re^3: pcre regex
in thread pcre regex

I substituted and changed ^ and $ but still not getting matches

(?<=)\d{4}[A-Z0-9](?=)

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Re^5: pcre regex
by moritz (Cardinal) on Apr 06, 2012 at 11:40 UTC

    What do you think (?<=) and (?=) do? Why did you write them?

    The regex you wrote matches a string like 4444B within a longer substring, so maybe you're doing something else wrong.

Re^5: pcre regex
by bart (Canon) on Apr 06, 2012 at 12:00 UTC
    This might do what yo uwant:
    \b\d{4}[A-Z0-9]\b
    The \b restricts the matches to word boundaries, so it won't report matches in the middle of a longer "word" (which may include digits), like "123456789ABCD".