This only populates the array up to the index corresponding to the highest value of $mon. 

__DATA__
CUSTA
1/2015 100
12/2015 1,000
CUSTB
2/2015 100
3/2015 100

[download]
Output: 
$VAR1 = {
          'CUSTA' => [
                       undef,
                       '100',
                       undef,
                       undef,
                       undef,
                       undef,
                       undef,
                       undef,
                       undef,
                       undef,
                       undef,
                       undef,
                       '1,000'
                     ],
          'CUSTB' => [
                       undef,
                       undef,
                       '100',
                       '100'
                     ]
        };

[download]

edit: provided working code

You can pre-populate the array of month values for each customer as you find it: 

    # note:
    #
    # @{ ... } turns the hash entry for this customer into an array.
    #
    # map creates a new list consisting of one element, undef, for eac
+h
    # element from the list it is given, i.e. @months

[download]
#!/usr/bin/perl

use strict;
use warnings;
use Data::Dumper;
$Data::Dumper::Sortkeys = 1;

my @months = qw/dummy jan feb mar apr may jun jul aug sep oct nov dec/
+;

my %report;
my $cust;

while (<DATA>) {
  chomp;
  if ( /^[A-Z]/ ) {
    $cust = $_;
    @{ $report{ $cust } } = map { undef } @months;
    next;
  }

  my ($date, $value) = split ' ', $_;
  my ($mon, $year)   = split '/', $date;

  $report{$cust}[$mon] = $value;
}
print Dumper(\%report);

__DATA__
CUSTA
1/2015 100
12/2015 1,000
CUSTB
2/2015 100
3/2015 100

[download]
Output: 
$VAR1 = {
          'CUSTA' => [
                       undef,
                       '100',
                       undef,
                       undef,
                       undef,
                       undef,
                       undef,
                       undef,
                       undef,
                       undef,
                       undef,
                       undef,
                       '1,000'
                     ],
          'CUSTB' => [
                       undef,
                       undef,
                       '100',
                       '100',
                       undef,
                       undef,
                       undef,
                       undef,
                       undef,
                       undef,
                       undef,
                       undef,
                       undef
                     ]
        };

[download]

Having said all that, however, this problem seems to be ill-suited for using an array. I would store the values in a hash and have the code that reads the hash (probably looping through @months) print 'undef' or a blank or whatever, if there's no value for the given months.


The way forward always starts with a minimal test.

In reply to Re^2: Reformat RAW Excel Data by 1nickt
in thread Reformat RAW Excel Data by techjohnny

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