<?php

function numbers_in_array($array)
{
   return array_filter($array, "is_numeric") ? FALSE : TRUE;
}

$data = array(
    "keepThis"   => array("x", "y", "z"),
    "RemoveThis" => array("3", "2", "1"),
    "keepThis2"  => array("x", "y", "z")
);

$filtered_data = array_filter($data, "numbers_in_array");

print_r($filtered_data);

?>