Formatting Number with Regular Expression

[eluser]pickupman[/eluser]
Try this:

Code:

$phone_str ='1234567890';
$result = preg_replace('/\(?\b([0-9]{3})\)?[-. ]?([0-9]{3})[-. ]?([0-9]{3})[-. ]?([0-9]{1})\b/si', '$1-$2-$3-$4', $phone_str);

var_dump($result);