Re: most idiomatic way to iterate over an associative array?
Date: Wed, 7 May 2008 17:19:04 -0700 (PDT)
Message-ID: <57867d79-6aff-4f44-b0aa-8798f4c521e6@c65g2000hsa.googlegroups.com>
On May 7, 4:37 pm, "stephen O'D" <stephen.odonn..._at_gmail.com> wrote:
> 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).- Hide quoted text -
>
> - Show quoted text -
Your are probably correct. My quick test failed however using table.count instead of table.last like I did would probably be a better idea and would be worth testing. It has been over 3 years since I wrote any PL/SQL code worth mentioning. After posting I though I should have tested table.first .. table.last also. Maybe tomorrow I will find some spare time.
- Mark D Powell --