Thomas Kennll:

You've got plenty of answers already, so I'll just play around a little:

$ cat u.pl
my $data = "Region Item volume Month";
my %h = do {my $cnt=0; map {$_=>++$cnt} split /\s+/, $data};
print "$_  $h{$_}\n" for grep {exists $h{$_}} qw(Item volume Tuba);

$ perl u.pl
Item  2
volume  3
[download]

The hash maps the fields with the field index. Wrapping the right hand side of the hash assignment in a do statement lets me localize a temporary variable. Preincrementing the temp variable converts the field numbers to one-based numbering.

...roboticus

When your only tool is a hammer, all problems look like your thumb.