perlfaq5: How can I output my numbers with commas added?

this is the shortest regex i can come up with that seems to work all in one 
line.

s/([+-])?(\d{1,3})(?=(\d{3})+)/$1$2,/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 seems to handle a leading +/- and existing commas

feedback appreciated.

pizza