jerrygo jerrygo - 3 months ago 17
Perl Question

Transpose in perl

I have started learning perl and like to try out new things.

I have some problem in text processing.
I have some text of the form,

0 1 2 3 4 5 6 7 8 9 10

6 7 3 6 9 3 1 5 2 4 6


I want to transpose this text. Like, I want to make rows as columns ans columns as rows. Id there a way to do this in perl?

Thank you all.

Answer

So this solution uses an array-of-arrays, each nested array is a row of data. Very simply you loop over the columns in each row and push them onto another array-of-arrays using the column index as the index which to push the value onto. This has the effect of pivoting the data as you requested.

#!/usr/bin/env perl

my @rows = ();
my @transposed = ();

# This is each row in your table
push(@rows, [qw(0 1 2 3 4 5 6 7 8 9 10)]);
push(@rows, [qw(6 7 3 6 9 3 1 5 2 4 6)]);

for my $row (@rows) {
  for my $column (0 .. $#{$row}) {
    push(@{$transposed[$column]}, $row->[$column]);
  }
}

for my $new_row (@transposed) {
  for my $new_col (@{$new_row}) {
      print $new_col, " ";
  }
  print "\n";
}

This results in:

0 6 
1 7 
2 3 
3 6 
4 9 
5 3 
6 1 
7 5 
8 2 
9 4 
10 6