You don't show the code you've already written so I'm going to assume that this is homework.

Have you thought about whether the problem would be easier if your array contained different values?

How would you approach the problem if your array contained ten elements like the following:

@array = (0..9);
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No, this isn't a homework but the final part of a script.

The result of my script is an array like this:

@array=(--, 0.0175, 0.0483, 0.0507, --, 0.0471, 0.0483, --, 0.0287, --)

the length of the array can be differ; depend by the input file

so if I print this array I obtain:

print @array;
--
0.0175
0.0483
0.0507
--
0.0471
0.0483
--
0.0287
--
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Instead I hope to have:

0
0.0175"\t"0
0.0483"\t"0.0471"\t"0
0.0507"\t"0.0483"\t"0.0287"\t"0
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So I tried to insert the array inside a variable and then split it into array

my $fileAverage = join "", @array;
$fileAverage =~ s/--\n/--0\n/g;
my (@matrix) = split('--', $fileAverage);
foreach my $lane (@matrix) {print "\t$lane";
}
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but I obtain:

"\t"0
0.0175
0.0483
0.0507
"\t"0
0.0471
0.0483
"\t"0
0.0287
"\t"0
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Maybe you want to think of it in a different way, by looking at how to divide the array across columns. If you build your columns and then print every row of your column, you should get your result. I'm going to first show you how to do it for a fixed number of columns and then how to expand that to an arbitrary number of columns:

my @column1;
my @column2;
my @column3;
my @column4;

while( @array and $array[0] ne '--') {
    push @column1, shift @array;
};
shift @array;
while( @array and $array[0] ne '--') {
    push @column2, shift @array;
};
shift @array;
while( @array and $array[0] ne '--') {
    push @column3, shift @array;
};
shift @array;
while( @array and $array[0] ne '--') {
    push @column4, shift @array;
};
shift @array;

for my $row (1..3) {
    print join "\t", $column1[$row], $column2[$row],$column3[$row],$co
+lumn4[$row];
    print "\n";
};
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Now, that only works for four columns. To make it work with any number of columns, we need to move away from the named column arrays and store all column arrays in another array ("AoA"):

my @column;

my $curr_column = 0;
my $rows = 0;
while( @array and ) {
    if( $array[0] ne '--' ) {
        $column[ $curr_column ] ||= []; # a new column
        push @{ $column[ $curr_column ] }, shift @array;
        if( $rows < $#{ $column[ $curr_column ] } ) {
            $rows = $#{ $column[ $curr_column ] };
        };
    } else {
        $index++;
        shift @array;
    };
};

for my $row (0..$rows) {
    print join "\t", map { $_->[ $row ] } @column;
    print "\n";
};
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I also tried with this code

my $count3="-1";
foreach my $lane (@array) {
    if ($lane eq "--\n"){$count3++;print "\t" x $count3 . "0\n";}
    else     {print "\t" x $count3 . "$lane"}
    }
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but I obtained:

0
0.0175
0.0483
0.0507
"\t"     0
"\t"     0.0471
"\t"     0.0483
"\t\t"          0
"\t\t"          0.0287
"\t\t\t"              0
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Do you have the freedom of adapting your data-structure? Here an array of arrays looks much more suitable than the one-dimensional array of values seperated by \n that you use.

HTH, Rata

#!/usr/bin/perl

# http://perlmonks.org/?node_id=1176395

use strict;
use warnings;

my @array;
$array[0]="0\n1\n2\n3\n";
$array[1]="4\n5\n6\n";
$array[2]="7\n8\n";
$array[3]="9\n";

my @result;

for my $start (0..$#array)
  {
  my $to = $start;
  $result[$to++] .= "\t" x !!$start . $1 while $array[$start] =~ /(.+)
+\n/g;
  }

print "$_\n" for @result;
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outputs:

0
1       4
2       5       7
3       6       8       9
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#!/usr/bin/perl
use strict;
use warnings;
use Data::Dumper;

my @array;
$array[0]="0\n1\n2\n3\n";
$array[1]="4\n5\n6\n";
$array[2]="7\n8\n";
$array[3]="9\n";

my @twod_array;

my $i_col=0;

foreach my $col (@array)
{
   my $i_row = $i_col; #we go down a diagonal to right
   
   my @row_stuff = split (' ',$col);
   foreach my $ele (@row_stuff)
   {
      $twod_array[$i_row++][$i_col] = $ele;
   }
   $i_col++;
}

foreach my $row_ref (@twod_array)
{
   my $line = join ("\t", @$row_ref);
   print "$line\n";
}

=prints:
0
1    4
2    5    7
3    6    8    9
=cut
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