#!/usr/bin/perl

# http://perlmonks.org/?node_id=1195332

use strict;
use warnings;

my @array = (
    ['X1','X2','X3','X4' ],
    ['','foo','',''],
    ['','bar','',''],
    ['','rat','',''],
    ['me','','','']
);

use Data::Dump 'pp';
print "before\n";
pp \@array;

my @newarray;
my @itemsincolumn;

my $width = @{ $array[0] };

for my $row ( @array )
  {
  for my $column ( 0 .. $width - 1 )
    {
    length $row->[$column] and
      $newarray[ $itemsincolumn[$column]++ ][$column] = $row->[$column];
    }
  }
for my $row ( @newarray )
  {
  $_ .= '' for $row->@[0 .. $width - 1];
  }

print "after\n";
pp \@newarray