clear an array

Greetings,

I have a multi-dimensional array (2 dimensions) within a FOR LOOP that I
want to reset for each iteration through the LOOP.  The number of rows
in the first dimension of the array may change for each iteration
through the LOOP.

So basically I need to set the rows back to zero for both dimensions in
this array.

Database version is 8.2.0.

Something like:

CREATE OR REPLACE FUNCTION processdata(integer)
  RETURNS varchar(99) AS
$BODY$

DECLARE

    in_batch_id ALIAS FOR $1;

    sp_parameters text[][];

    sp_row_data customers%ROWTYPE;

    sp_parameter_id text := '';
    sp_parameter_value varchar(50) := '';


    BEGIN

        FOR sp_row_data IN SELECT * FROM customer_rules
            WHERE filetypeid = in_batch_id LOOP

            -- Get parameter id
            sp_parameter_id := sp_row_data.ruleparameterid;

            -- Get parameter source
            sp_parameter_source := sp_row_data.parametersource;

            -- populate array
            sp_parameters := array_cat(sp_parameters,
array[sp_parameter_id, sp_parameter_value]);


            -- do something with array

            -- clear array
            -- WHAT IS THE CODE HERE!?!?



        END LOOP;

    END;


$BODY$
  LANGUAGE 'plpgsql' VOLATILE;




Thanks in advance,
James