Trim the string elements of an array in PostgreSQL (wrap this function around an array or another function that returns an array, like string_to_array).

array_trim.sql

CREATE OR REPLACE FUNCTION array_trim(text[])
RETURNS text[]
AS
$$
DECLARE
   text ALIAS FOR $1;
   retVal text[];
BEGIN
   FOR I IN array_lower(text, 1)..array_upper(text, 1) LOOP
    retVal[I] := trim(text[I]);
   END LOOP;
RETURN retVal;
END;
$$
LANGUAGE plpgsql 
   STABLE 
RETURNS NULL ON NULL INPUT;

Example usage:

A field in the table has an array that looks like this:

{"Homeowner Exemption"," Senior Exemption"," Senior Freeze Exemption"}

There are spaces before the two instances of the word "Senior". Now, the method that input this data into the field could have trimmed the spaces off of the strings but it didn't, so we need to use Postgres to trim the spaces.

SELECT array_trim('{"Homeowner Exemption"," Senior Exemption"," Senior Freeze Exemption"}')
-- results in:
-- {"Homeowner Exemption","Senior Exemption","Senior Freeze Exemption"}