I am not sure if this fits your oracle version. On my 10g I can use pipelined table functions:
set serveroutput on
create type number_list as table of number;
-- since you want this solution
create or replace function split_csv (i_csv varchar2) return number_list pipelined
is
mystring varchar2(2000):= i_csv;
begin
for r in
( select regexp_substr(mystring,'[^,]+',1,level) element
from dual
connect by level <= length(regexp_replace(mystring,'[^,]+')) + 1
)
loop
--dbms_output.put_line(r.element);
pipe row(to_number(r.element, '999999.99'));
end loop;
end;
/
insert into foo
select column_a,column_b from
(select column_value column_a, rownum rn from table(split_csv('0.75, 0.64, 0.56, 0.45'))) a
,(select column_value column_b, rownum rn from table(split_csv('0.25, 0.5, 0.65, 0.8'))) b
where a.rn = b.rn
;