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

From: Mark D Powell <Mark.Powell_at_eds.com>
Date: Wed, 7 May 2008 09:28:47 -0700 (PDT)
Message-ID: <2f0ed2dd-f358-49bd-aa69-93a18bffa8ed@m3g2000hsc.googlegroups.com>

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...http://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 -- Received on Wed May 07 2008 - 11:28:47 CDT