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