Format Phone Number (Custom Function)

format-phone.php

<?php
/**
 * Format Phone Number
 *
 * This function takes a 10 digit phone number and formats it
 */

function format_phone($s) {
$rx = "/
    (1)?\D*     # optional country code
    (\d{3})?\D* # optional area code
    (\d{3})\D*  # first three
    (\d{4})     # last four
    (?:\D+|$)   # extension delimiter or EOL
    (\d*)       # optional extension
/x";
preg_match($rx, $s, $matches);
if(!isset($matches[0])) return false;

$country = $matches[1];
$area = $matches[2];
$three = $matches[3];
$four = $matches[4];
$ext = $matches[5];

$out = "$three-$four";
if(!empty($area)) $out = "$area-$out";
if(!empty($country)) $out = "+$country-$out";
if(!empty($ext)) $out .= "x$ext";

// check that no digits were truncated
// if (preg_replace('/\D/', '', $s) != preg_replace('/\D/', '', $out)) return false;
return $out;
}

functions.php

/** Add function to format phone numbers */
require_once( 'library/format-phone.php' );

phone-number.php

<?php echo format_phone($phone_number); ?>