I needed a showing of choices in the drop down list according to some criterion (object status, in my case). So, I used an array slices instead use loop.I hope that this decision will be usefull somebody. ;) 

my @list = ( [0, 'Zero'], [1, 'One'], [2, 'Two'], [3, 'Three'], 
             [4, 'Four'], [5, 'Five'], [6, 'Six'] );

SWITCH: for ($some_obj->get_status) {
    /0/ && do { @list = @list[0, 6]; last; };
    /1/ && do { @list = @list[0..2]; last; };
    /2/ && do { @list = @list[2..5]; last; };
    /3/ && do { @list = @list[3];    last; };
    /4/ && do { @list = @list[4];    last; }; 
    /5/ && do { @list = @list[2, 5]; last; };
    /6/ && do { @list = @list[6];    last; };
                @list = ();
}

$"=', ';

print "Result: status = ".$some_obj->get_status."; list=@list";

[download]

Replies are listed 'Best First'.
Re: Use an array slices
by Hofmator (Curate) on Feb 28, 2003 at 09:30 UTC
    An alternative to the 'switch' is using a dispatch array. I'm assuming for the following that $some_obj->get_status returns an integer number, otherwise this number has to be extracted from the return value: 
    # choice number  0       1       2     3    4     5     6
my @choices = ([0,6], [0..2], [2..5], [3], [4], [2,5], [6]);

my $num = $some_obj->get_status;
my @newlist = @list[ @{ $choices[$num] } ];

local $"=', ';

print "Result: status = $num; list=@newlist";

    [download]

    -- Hofmator

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[d/l]
Re: Use an array slices
by blakem (Monsignor) on Feb 28, 2003 at 09:31 UTC
    Have you thought about what happens when you add the tenth (i.e. '10') branch?

    -Blake

[reply]
      This decision doesn't have pretensions on absolutly universality. I have just had a case with fixed choises. If I will add the tenth branch, I will add a choice for it. 
      #!/usr/bin/perl -w

use strict;

      [download]
[reply]
[d/l]
        I assume that case would look something like this: 
        #!/usr/bin/perl -wT
use strict;

my $value = 10;

SWITCH: for ($value) {
    /0/  && do {print "ZERO\n"; last; };
    /1/  && do {print "ONE\n";  last; };
    /10/ && do {print "TEN\n";  last; };
                print "NONE OF THE ABOVE\n";
}

        [download]
        Can you guess what the output is? Run it and find out.

        -Blake

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[d/l]

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