$re = '/^[-()+ .]?(?:[0-9]+[-()+ .]+)+[0-9]+$/m';
$str = '9999 999 999
+91 99 99 99 9999
999.999.999
99999999
677887 78787
99 (999) 99 99
9999 999 999
+91 99 99 99 9999
999.999.999';
$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