A needed a function to find the keys which contain part of a string, not equalling a string...

<?php
function array_keys_contain($input, $search_value, $strict = false)
    {
        $tmpkeys = array();

        $keys = array_keys($input);

        foreach ($keys as $k)
        {
            if ($strict && strpos($k, $search_value) !== FALSE)
                $tmpkeys[] = $k;
            elseif (!$strict && stripos($k, $search_value) !== FALSE)
                $tmpkeys[] = $k;
        }

        return $tmpkeys;
    }
?>