#!/usr/bin/perl -w

use strict; 

# here we have an irregular sized 2D array
my @array = ( [1],[2,2],[3,3,3],[4,4,4,4] );
my $all ='42';

# this sets all elements to $all
for (@array) {
  @$_ = ($all) x @$_;
}

# this also sets all elements to $all
# map is just the loop above in short form 
map{ @$_ = ($all) x @$_ }@array;

# this prints the entire structure
for (@array) {
  for (@$_) {
      print "-",$_;
  }
  print"\n";
}

##</code><code>##

map{ push @list, @$_ }@array;
print "@list";