>>> $a = "23wef32fdd2112";
=> "23wef32fdd2112"
>>> preg_match_all("/(?:(?P<some>[\d]+)|(?P<any>[a-z]+))/", $a, $matches)
=> 5
>>> $matches
=> [
     0 => [
       "23",
       "wef",
       "32",
       "fdd",
       "2112",
     ],
     "some" => [
       "23",
       "",
       "32",
       "",
       "2112",
     ],
     1 => [
       "23",
       "",
       "32",
       "",
       "2112",
     ],
     "any" => [
       "",
       "wef",
       "",
       "fdd",
       "",
     ],
     2 => [
       "",
       "wef",
       "",
       "fdd",
       "",
     ],
   ]
>>>