$re = '/(?<=[\d ])[()-]+ */i';
$str = 'firstname lastname (123) 456-7890
firstname lastname (234) 567-8910
firstname last-name 345-678-9101';
$subst = "";
$result = preg_replace($re, $subst, $str);
echo "The result of the substitution is ".$result;
Please keep in mind that these code samples are automatically generated and are not guaranteed to work. If you find any syntax errors, feel free to submit a bug report. For a full regex reference for PHP, please visit: http://php.net/manual/en/ref.pcre.php