I asked a similar question earlier. due to my bad example, i sidetracked the helpful commentators. Basically, i need to incrementally add to a multi-dimensional array. In addition, i can't dynamicaly deal with a variable number of dimensions (instead of with code specific to each dimension).

also, if you have another way to structure this, i would appreciate comments. last time, there were suggestions to use a hash with composite keys. i guess i still don't see its benefit yet. 

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

my $ranges = [
    [
      { I => 3, },
      { I => 4, },
      { I => 2, },
      { I => 6, },
      { I => 9, },
    ],
    [
      { I => 3, J => 2, },
      { I => 4, J => 3, },
      { I => 3, J => 4, },
      { I => 3, J => 6, },
      { I => 4, J => 0, },
      { I => 4, J => 1, },
    ],
    [
      { I => 4, J => 3, K => 2, },
      { I => 4, J => 3, K => 1, },
      { I => 4, J => 2, K => 2, },
      { I => 2, J => 3, K => 2, },
      { I => 6, J => 2, K => 1, },
    ],
];

my $loop =0;
foreach my $rngGrp ( @{ $ranges } ) {
    my $ds;
    my $f=0;
    foreach my $rngHash ( @{ $rngGrp } ) {

        my @rngList = sort keys %$rngHash;
        my ($ii,$vi,$ij,$vj,$ik,$vk);

        if    ( scalar @rngList == 1 ) {
            $ii = $rngList[0];
            $vi = $rngHash->{$ii};
            $ds->[$vi] = "line $f";
        }
        elsif ( scalar @rngList == 2 ) {
            $ii = $rngList[0];
            $vi = $rngHash->{$ii};
            $ij = $rngList[1];
            $vj = $rngHash->{$ij};
            $ds->[$vi]->[$vj] = "line $f";
        }
        elsif ( scalar @rngList == 3 ) {
            $ii = $rngList[0];
            $vi = $rngHash->{$ii};
            $ij = $rngList[1];
            $vj = $rngHash->{$ij};
            $ik = $rngList[2];
            $vk = $rngHash->{$ik};
            $ds->[$vi]->[$vj]->[$vk] = "line $f";
        }

        $f++;
    }
    if    ( $loop == 0 ) { 
        $ds->[6] = "new line";
        $ds->[9] = "newer line";
    }
    elsif ( $loop == 1 ) {
        $ds->[4]->[0] = "new line";
        $ds->[3]->[6] = "newer line";
    }
    elsif ( $loop == 2 ) {
        $ds->[2]->[3]->[2] = "new line";
        $ds->[6]->[2]->[1] = "newer line";
    }
    $loop++;

    print "DS = $ds\n";
    print Dumper $ds;
    print "\n\n";
}

[download]

note that the $ds variable is NOT outside the outer loop. The outer loop represents both the incremental addition to a multidimensional array as well as the variable number of dimensions.

note the inner loop is composed of two functions; one to build/add to an array and one to overwrite existing indicies. this code is part of a huge program and the accessing and modification is a big part of the program.

previous suggestions worked only for the first array of each range. i failed to emphasize that i need to add new indicies to an already existing array. to me, that makes it hard.

In reply to incremental additions to multidimensional arrays by Anonymous Monk

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