The 1 at the start of the line does nothing - see it as a nop (no operation). Well, to be honest, it does something: It evaluates to 1, if you would use it. It could also be written as 
while (s(\d)(\d\d\d)(?!\d)/$1,$2/) {};

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If you count the characters this line is a little longer, but not really more readable.
--
use signature; signature(" So long\nAlfie");

In reply to Re: Regular expression by alfie
in thread Regular expression by nysus

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