^([1-9]\d*)$|^(\d+\.\d)$|^(\d+\.\d\d)$

$a = ".10";
$zz = '/^([1-9]\d*)$|^(\d+\.\d)$|^(\d+\.\d\d)$/';
var_dump(preg_match($zz,$a));

破罐子互摔