I am parsing the flatfile into an AoH. This makes it very easy to get at a row, than a column. Please note the cool map that creates the reference to a hash.

foo.txt
--------------------------
ID    NAME1    NAME2    AGE
1    donald    duck    50
2    mickey    mouse    48
3    peter    pan    62
4    madre    theresa    108
5    banana    split    2 

#!/usr/bin/perl -w
use strict;
use IO::File;
 
my $fh = new IO::File;
 
 
$fh->open("< foo.txt") or die "can't open foo.txt $!";
 
my @file = map{ [split /\s+/]; } <$fh>;
 
my $keys = shift @file;
 
print "The keys are:\n";
print join("\t",@$keys )."\n";
my @aoh = map{ my %hash; @hash{@$keys} = @$_; \%hash} @file;
 
print "Row 3 is \n";
print join("\t", @{$aoh[2]}{@$keys} )."\n"; 
 

print "Column 'NAME2' is:\n";
foreach my $row (@aoh) {
  print $row->{NAME2}."\n";
}
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