$re = '/^(?![A-Za-z]\d?$)[a-zA-Z]+\d*$/m';
$str = 'tt
tt2
test
a11
t2
t
1
t1t';
preg_match_all($re, $str, $matches, PREG_SET_ORDER, 0);
// Print the entire match result
var_dump($matches);
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