Rather than updating the phone number with REs, why not: 

my $phone = '1234567890';
printf("(%s)%s-%s\n", unpack "A3 A3 A*", $phone);

[download]
printf(), sprintf() and unpack() functions are generally considered efficient.

In reply to Re: formatted phone number from variable by jaa
in thread formatted phone number from variable by powerhouse

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