Re: Using Map to Create AoA

There is no need to save the index as part of this, as that information is retained by the AoA itself. You have to make the best design decision "one truth is only stored once"

use Data::Dumper;
use strict;
use warnings;

my $arr = ['A -4 C','C -4 B','B -4 A','A -2 C','C -3 B'];
my @a = map {[split " ",$_]} @$arr;
print Dumper(\@a);
[download]

This prints:

$VAR1 = [
          [
            'A',
            '-4',
            'C'
          ],
          [
            'C',
            '-4',
            'B'
          ],
          [
            'B',
            '-4',
            'A'
          ],
          [
            'A',
            '-2',
            'C'
          ],
          [
            'C',
            '-3',
            'B'
          ]
        ];
[download]

Comment on Re: Using Map to Create AoA Select or Download Code

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Re^2: Using Map to Create AoA by neversaint (Deacon) on Oct 16, 2005 at 16:12 UTC
You have to make the best design decision "one truth is only stored once" Thanks for the very useful advice pg. My code above is just a small portion of a larger program I have. In this case I have to keep the index, cause I need to process the array, which will loose its order later. Subsequently I need to 'remember' those position to be able to callback certain value. You are welcome to see my recent postings and especially this, related and similar to this problems. --- neversaint and everlastingly indebted.......	[reply]
Re^3: Using Map to Create AoA by Tanktalus (Canon) on Oct 16, 2005 at 16:21 UTC
Personally, I'd do this using an AOH. That keeps the data separate from the index, allowing the data to change format later without having to change other code (yes, you can use the -1 index, but all you have to do is use '3' as your index once to get confounded by later changes), and also allowing easy access to the original data without having to play with it: `#!/usr/bin/perl -w use strict; my $arr = ['A -4 C','C -4 B','B -4 A','A -2 C','C -3 B']; my @a = do { my $idx = 0; map { { data => [ split ' ', $_ ], idx => $idx++, } }@$arr }; use Data::Dumper; print Dumper(\@a);` [download] This gives: Read more... (1420 Bytes) If you really want it in a single AoA, then change the map like this: `my @a = do { my $idx = 0; map { [ (split ' ', $_), $idx++ ], }@$arr };` [download] HTH	[reply] [d/l] [select]
Re^3: Using Map to Create AoA by pg (Canon) on Oct 16, 2005 at 16:15 UTC
If this is the case, then we do this: `use Data::Dumper; use strict; use warnings; my $arr = ['A -4 C','C -4 B','B -4 A','A -2 C','C -3 B']; my @a = map {[split " ", $arr->[$_] . " $_"]} (0 .. @$arr - 1); print Dumper(\@a);` [download] Which gives: `$VAR1 = [ [ 'A', '-4', 'C', '0' ], [ 'C', '-4', 'B', '1' ], [ 'B', '-4', 'A', '2' ], [ 'A', '-2', 'C', '3' ], [ 'C', '-3', 'B', '4' ] ];` [download]	[reply] [d/l] [select]