如何正确传递$ _POST数据以使用filter_input_array切换case语句

GOAL: echo switch statement case which maps/matches to 'postType'

PROBLEM: Regardless of what I try, the $_POST data seems to vanish, thus the switch statements default case is triggered and the form shows again instead of the intended/desired echo statement that I hope to show based on the postType contained within the $filter variable. I am working in PHP 5.4

A var_dump returns: array(2) { ["postType"]=> NULL ["myContent"]=> string(4) "dsfs" }

I believe that I have both the form and the switch statement syntaxs/formatting correct. My problem, i think is somewhere in how the data is or isn't being passed to the switch via the filter_input_array(INPUT_POST, [...])

my humble code stub:

//test data
//$_POST = [ 'postType' => 'myPlayby',  'myContent' => 'Anna King', ];


//build the array of data created by from for switch checks
$filter = filter_input_array(INPUT_POST, [ 'postType'   => [], 'myContent'  => [], ]);


var_dump($filter);
echo "<br /><br />";


//$search = false;
switch ($filter['postType'])
{
case 'myChar':
    echo "Character Check: " . $filter['myCharacter'];
    $search = $filter['myCharacter'];
    break;

//test data ought to trigger myPlayby case showing 'Playby check: Anna King' here... frack
case 'myPlayby':
    echo "Playbe Check: " . $filter['myPlayby'];
    $search = $filter['myPlayby'];
    break;
case 'myFoobar':
    echo "Foo Check: " . $filter['myFooBar'];
    $search = $filter['myFooBar'];
    break;
default:
    echo '<form type="submit" method="post" action="' . THIS_PAGE . '"; >
        <select name="postTypes">
        <option default disable>-------------</option>
        <option value="myChar">Character</option>
        <option value="myPlayby">Playby</option>
        <option value="myFooBar">Foo</option>
        </select> 
        <input type="text" value="" name="myContent"/>
        <input type="submit" name="submit" value="Submit"> 
        </form>' ;
    break;
} 

This is my first time working with filter_input_array to handle $_POST data, and after a day of trial, error, research and effort which include looking at Lynda.com, searching Google and reading what relevant posts I could find on StackOverflow, php.net, etc, I am flummoxed.

I've found the answer, i was correct in that the issue was in how I set up the filter_input_array.

By refactoring the code like so:

$filter = filter_input_array(INPUT_POST, [
  'postType'    => [ 'filter' => FILTER_SANITIZE_STRING ],
  'contents'    => [ 'filter' => FILTER_SANITIZE_STRING ],
]);

$search = false; //in the switch, false is reassigned value of the sanitized string and all is happiness