How can I output my numbers with commas added?

i offer the following regex in replacement to Mr. Goldberg's:

s/(^[-+]?\d+?(?=(?>(?:\d{3})+)(?!\d))|\G\d{3}(?=\d))/$1,/g;

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#!/usr/bin/perl -l
$_ = "-10,000000";
s/([+-])?(\d{1,3})(?=(\d{3})+)/$1$2,/g;
print;
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it should handle explicit leading negation/addition as well as existing commas

pizza