PHP regex vs explode() for phone number - php

Question

I have been messing around with some regular expressions, and I ran into a small hiccup with a more complicated version of my phone number formatting.
Here's what I am working with:
$number1 = '[phone]';
$number1 = '[phone] x555';
These strings are actually being output from the MySQL query I created, and I love it.
However, I'm making a simple php function to auto-format the subscribers number from 1234567 to 123-4567.
I'm not too concerned about any number that doesn't start with +1. So I'm formatting US and Canadian numbers.
Here's what I attempted, if there was only 7 digits, and if the string starts with +1
<?php
function format_phonenumbers($phone){
if(empty($phone)){ return ''; }
$exploded = explode(' ',$phone);
$countrycode = $exploded[0];
$areacode = $exploded[1];
$number = $exploded[2];
$ext = (!empty($exploded[3])?$exploded[3]:'');
if($countrycode=='+1'){
$strphone = strlen($number);
if ($strphone == 7) { // auto-format US PHones
$prefix = substr($number,0,3);
$suffix = substr($number,-4);
}
$phone = $countrycode.' '.$areacode.' '.$prefix.'-'.$suffix.' '.$ext;
}
return $phone;
}
echo format_phonenumbers('[phone]'); // US domestic
echo '<br>';
echo format_phonenumbers('[phone] x555'); // international
?>
This formats what I need, but I'm curious if anyone believes I can do this in a better way. Like using a regex checker, that finds anything after the parenthesis, but before an extension, rather than using the explode() function.

Answer 1

Something like:
function format_phonenumbers($phone)
{
return preg_replace_callback(
'/([)]\s*)(\d{3,3}(\d+)/',
function ($match) {
return $match[1] . $match[2] . '-' . $match[3];
},
$phone
);
}
This should work, but requires PHP 5.3.0 or higher (if not you'll have to use create_function). Its arguable if it is any better however.