From perlfaq5:
This regexp will add commas to numbers: 
s/(^[-+]?\d+?(?=(?>(?:\d{3})+)(?!\d))|\G\d{3}(?=\d))/$1,/g;

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Originally posted as a Categorized Answer.

In reply to Re: How do I add commas to a number? by spadacciniweb
in thread How do I add commas to a number? by vroom

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