You are passing the argument to the subroutine, but your subroutine is not using it (it is using the uninitialized $item from the file scope). When you pass parameters to a subroutine, those values will be available in the special @_ array within the subroutine. You need to either use the @_element directly ($_[0] in your case), or assign a copy of it to another variable. Try starting your subroutine like:

sub some_sub {
    my $item = shift;
    my $string;
    # rest of subroutine
}
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Just so you know: the shift() function, when not given an array to shift from will automatically shift from @_ inside of a subroutine, or @ARGV otherwise.

Tuna, it is possible to do what you want using something called a dispatch table. It's simply a hash, where the key is what you are searching for, and the value is what you want if you find an exact match for the key. Below is your example re-worked to use a dispatch table:

#!/usr/bin/perl -w

use strict;

my %number_to_word = (
  1 => 'one',
  2 => 'two',
  3 => 'three',
);

my @numbers = qw(1 2 3 4);

foreach my $number (@numbers) {
  print "My number is ", $number_to_word{$number} || 'four', "\n";
}
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Please note that if $number isn't a match in %number_to_word, we'll default to printing four, using the || operator. This neatly covers your else condition.

One big advantage of using a dispatch table over an if/elsif/else statement is that it's much simpler to add and debug new conditions that you were aware of during the initial design.

Also, if you're looking to translate numbers to words you might want to check out the CPAN module Lingua::EN::Nums2Words. It has a method called num2word which can translate any number you supply to it into the corresponding english word.

sub some_sub{
        my $item = shift;  #assign the first element of @_ to $item
    my ($string);

    if ($item == 1){   #note == not = or = =
        $string = 'one';
    }
    if ($item == 2){
        $string = 'two';
    }
    # and so on ...
    print "My number is $string."
}
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Checkout perlop and perlsub.

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Coyote