function extract_only_numbers($s) {
$len = strlen($s);
$numbers = "";
for ($i = 0; $i < $len; $i++) {
$ch = $s[$i];
if (ctype_digit($ch)) {
$numbers = $numbers . $ch;
}
}
return $numbers;
}
$s = "c++14@vb.net&%java*() php <>/python 3.7.3";
echo extract_only_numbers($s);
/*
run:
14373
*/