$re = '/^(-?(?:(?=[1-9]|0(?!\d))\d+(?:\.\d+)?)|\.\d+)$/m';
$str = '0
1
0.2
1.23
-12
.234
00
0123
1223332.4434
02.4232
-3.343';
preg_match_all($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