Re: Unfolding a nDeep structure

tye's modules to the rescue! Algorithm::Loops to handle the variable number of nested foreach-loops, and Data::Diver to handle the multi-dimensional array indexing.

# (untested)
use Data::Diver qw[Dive DiveVal];
use Algorithm::Loops 'NestedLoops';

NestedLoops(
  [ ( [0..$dimension-1] ) x $depth ],
  sub {
     my @indices = @_;
     my $val = Dive( \@multi_dimensional_array, @indices );

     ## do something with $val. say, push it to an array
  }
);
[download]

Update: Just noticed that you wanted to know how to initialize this big structure to zeroes. The Dive sub doesn't autovivify, but DiveVal does:

## initialization

my @multi_dimensional_array;

NestedLoops(
  [ ( [0..$dimension-1] ) x $depth ],
  sub {
     DiveVal( \@multi_dimensional_array, @_ ) = 0;
  }
);
[download]

blokhead

Comment on Re: Unfolding a nDeep structure Select or Download Code

Replies are listed 'Best First'.
Re^2: Unfolding a nDeep structure by FFRANK (Beadle) on Jul 05, 2007 at 21:23 UTC
Thank you blockhead, I've been playing a bit with Dive. This would be part of a script were data is fed to @MDAsomeIndex in the form +1. I do not not have it behaving this way: `#!/usr/bin/perl -w use strict; use Data::Diver qw[Dive DiveVal]; use Algorithm::Loops 'NestedLoops'; my @MDA; my $dimension = 3; my $depth = 2; NestedLoops( [ ( [0..$dimension-1] ) x $depth ], sub { DiveVal( \@MDA, @_ ) = 0; } ); $MDA[0][0] += 1; my @AoA; for my $level (0..$dimension-1) { NestedLoops( [ ( [0..$dimension-1] ) x ($depth-1) ], sub { my @indices = @_; my $val = Dive( \@MDA, @indices ); push @{$AoA[$level]}, @$val; } );} for my $row (0..$#AoA) { print "@{$AoA[$row]}\n"; }` [download] Prints: 1 0 0 0 0 0 0 0 0 1 0 0 0 0 0 0 0 0 1 0 0 0 0 0 0 0 0 Updated: Expected: 1 0 0 0 0 0 0 0 0 ???	[reply] [d/l]
Re^3: Unfolding a nDeep structure by blokhead (Monsignor) on Jul 05, 2007 at 23:13 UTC
If I understand right (from looking at your example code in the OP), you want a structure that looks like this: `@AoA = ( [ $MDA[0][0][0], $MDA[0][0][1], ... , $MDA[0][2][2] ], [ $MDA[1][0][0], $MDA[1][0][1], ... , $MDA[1][2][2] ], [ $MDA[2][0][0], $MDA[2][0][1], ... , $MDA[2][2][2] ], );` [download] In other words, `$AoA[x]` contains all the elements of the form `$MDA[x][][]`, if you follow my notation. I don't see how this corresponds with your "Expected" data, but one thing I noticed is that you should make the following change: `# my $val = Dive( \@MDA, @indices ); # push @{$AoA[$level]}, @$val; my $val = Dive( $MDA[$level], @indices ); push @{$AoA[$level]}, $val;` [download] Because when dealing with `$AoA[$level]`, you only care about things starting form `$MDA[$level]`. Also, then $val will not be an arrayref like it was before. There are many equivalent ways to write this, but another way is the following: Here you can replace the entire foreach loop with this: `NestedLoops( [ ( [0..$dimension-1] ) x ($depth-1) ], sub { my @indices = @_; my $val = Dive( \@MDA, @indices ); push @{ $AoA[$indices[0]] }, $val; } );` [download] To explain this, it takes everything of the form `$MDA[a][b][c]` and pushes it onto the array at `$AoA[a]`. blokhead	[reply] [d/l] [select]


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