src/Routing/Route.php
protected function getOnlyStringKeys(array $array)
    {
        $allowed = array_filter(array_keys($array), function ($key)
        {
            return ! is_int($key);
        });

        return array_intersect_key($array, array_flip($allowed));
    }
protected function getOnlyStringKeys(array $array)
    {
        $allowed = array_filter(array_keys($array), function ($key)
        {
            return ! is_int($key);
        });

        return array_intersect_key($array, array_flip($allowed));
    }
protected function getOnlyStringKeys ( array $ array ) { $ allowed = array_filter ( array_keys ( $ array ) , function ( $ key ) { return ! is_int ( $ key ) ; } ) ; return array_intersect_key ( $ array , array_flip ( $ allowed ) ) ; }
Get arrays elements that contains only associative keys

@param array $array
@return array
Get arrays elements that contains only associative keys