How do you using $_POST values to create an associative array

Question

I am trying to divide $_POST values into different arrays to check its values. I am trying to retain both the $key and $values as an associative array. For now, only array_push works, but not array_merge. Array_merge returns an empty array for me. Can someone help?

$reg_word = $reg_alpha = $reg_paragraph = array();


foreach ($_POST as $key=>$value){
        if (in_array($key, $alpha_numbers)){    
            array_push($reg_word, $value);
        } else

        if (in_array($key, $alpha)){
            array_push($reg_alpha, $value);
        } else

        if (in_array($key, $paragraph)){
            array_push($reg_paragraph, $value);
        }
    }

Displays

Array ( [0] => St. John [1] => M [2] => kjkjk ) 
Array ( [0] => HKG ) 
Array ( [0] => kjkj )

I want it to display Array( Location => St. John) etc.

Answer 1

Then stop using array_push(); just assign.

$arr[$key] = $val;