$string =~ /^\d{4}(?:\,\d{4})*$/

... start, 4 digits, then any number of comma followed by 4 digits up to end (and then stop).

... and having validated, then you can split(/,/, $string) to "capture" the numbers.

In reply to Re: Validating Comma Delimited String by gone2015
in thread Validating Comma Delimited String by Anonymous Monk

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