EDIT: Я смешал и изменил два из приведенных ниже ответов, чтобы сформировать полную функцию, которая теперь делает то, что я хотел, а затем некоторые... Поэтому я решил, что опубликую его здесь, в случае, если кто-то еще ищет то же самое.
/*
* Function to analyze string against many popular formatting styles of phone numbers
* Also breaks phone number into it respective components
* 3-digit area code, 3-digit exchange code, 4-digit subscriber number
* After which it validates the 10 digit US number against NANPA guidelines
*/
function validPhone($phone) {
$format_pattern = '/^(?:(?:\((?=\d{3}\)))?(\d{3})(?:(?<=\(\d{3})\))?[\s.\/-]?)?(\d{3})[\s\.\/-]?(\d{4})\s?(?:(?:(?:(?:e|x|ex|ext)\.?\:?|extension\:?)\s?)(?=\d+)(\d+))?$/';
$nanpa_pattern = '/^(?:1)?(?(?!(37|96))[2-9][0-8][0-9](?<!(11)))?[2-9][0-9]{2}(?<!(11))[0-9]{4}(?<!(555(01([0-9][0-9])|1212)))$/';
//Set array of variables to false initially
$valid = array(
'format' => false,
'nanpa' => false,
'ext' => false,
'all' => false
);
//Check data against the format analyzer
if(preg_match($format_pattern, $phone, $matchset)) {
$valid['format'] = true;
}
//If formatted properly, continue
if($valid['format']) {
//Set array of new components
$components = array(
'ac' => $matchset[1], //area code
'xc' => $matchset[2], //exchange code
'sn' => $matchset[3], //subscriber number
'xn' => $matchset[4], //extension number
);
//Set array of number variants
$numbers = array(
'original' => $matchset[0],
'stripped' => substr(preg_replace('[\D]', '', $matchset[0]), 0, 10)
);
//Now let check the first ten digits against NANPA standards
if(preg_match($nanpa_pattern, $numbers['stripped'])) {
$valid['nanpa'] = true;
}
//If the NANPA guidelines have been met, continue
if($valid['nanpa']) {
if(!empty($components['xn'])) {
if(preg_match('/^[\d]{1,6}$/', $components['xn'])) {
$valid['ext'] = true;
}
}
else {
$valid['ext'] = true;
}
}
//If the extension number is valid or non-existent, continue
if($valid['ext']) {
$valid['all'] = true;
}
}
return $valid['all'];
}