Re: most idiomatic way to iterate over an associative array?

On May 7, 5:28 pm, Mark D Powell <Mark.Pow..._at_eds.com> wrote:
> On May 7, 4:07 am, Robert Klemme <shortcut..._at_googlemail.com> wrote:
>
>
>
> > On May 7, 6:51 am, m..._at_pixar.com wrote:
>
> > > This is what I'm doing now... is there a better way?
> > > It would be great if there were some construct such
> > > as 'for i in x begin ... end;'
>
> > > i := x.first;
> > > loop
> > > dbms_output.put_line(i);
> > > exit when i = x.last;
> > > i := x.next(i);
> > > end loop;
>
> > > Many TIA!
> > > Mark
>
> > This will break for empty collections. You can do
>
> > SQL> set serverout on
> > SQL> DECLARE TYPE population_type IS TABLE OF NUMBER INDEX BY
> > VARCHAR2(64);
> > 2 continent_population population_type;
> > 3 which VARCHAR2(64);
> > 4 BEGIN
> > 5 dbms_output.put_line('-----------');
> > 6
> > 7 which := continent_population.FIRST;
> > 8 while which is not null loop
> > 9 dbms_output.put_line(which || ' -> ' ||
> > continent_population(which));
> > 10 which := continent_population.NEXT(which);
> > 11 end loop;
> > 12
> > 13 dbms_output.put_line('-----------');
> > 14
> > 15 continent_population('Australia') := 30000000;
> > 16 continent_population('Antarctica') := 1000; -- Creates new
> > entry
> > 17 continent_population('Antarctica') := 1001; -- Replaces
> > previous value
> > 18
> > 19 which := continent_population.FIRST;
> > 20 while which is not null loop
> > 21 dbms_output.put_line(which || ' -> ' ||
> > continent_population(which));
> > 22 which := continent_population.NEXT(which);
> > 23 end loop;
> > 24
> > 25 dbms_output.put_line('-----------');
> > 26 END;
> > 27 /
> > -----------
> > -----------
> > Antarctica -> 1001
> > Australia -> 30000000
> > -----------
>
> > PL/SQL procedure successfully completed.
>
> > SQL>
>
> > Cheers
>
> > robert
>
> > seehttp://download.oracle.com/docs/cd/B19306_01/appdev.102/b14261/collec......
>
> I think I would consider the For I in 1..n construct
>
> UT1 > l
> 1 declare
> 2 type t_array is table of varchar2(10) index by binary_integer;
> 3 t_list t_array;
> 4 begin
> 5 t_list(1) := 'one';
> 6 t_list(2) := 'two';
> 7 t_list(3) := 'three';
> 8 t_list(4) := 'four';
> 9 t_list(5) := 'five';
> 10 for I in 1..t_list.last loop
> 11 dbms_output.put_line(t_list(I));
> 12 end loop;
> 13* end;
> UT1 > /
> one
> two
> three
> four
> five
>
> PL/SQL procedure successfully completed.
>
> Again as Robert warned in his solution the array should not be empty.
>
> HTH -- Mark D Powell --

I am fairly sure if you do

for i in 1 .. v_array.count loop
  null;
end loop;

It will happily handle an empty array (don't have access to Oracle right now to check). Received on Wed May 07 2008 - 15:37:18 CDT