my @array = qw(1 2 3);
@array = qw(one two three) if $op eq 'alpha';

##</code><code>##

my @xxx;
@xxx = qw(one two three) if $op eq 'numbers';
@xxx = qw(four five) if $op eq 'alpha';
@xxx = qw(six ten) if $op eq 'alp';

##</code><code>##

#!/usr/bin/perl -w
use strict;

hello('world');
goodbye('world');

sub hello {
    my $greeting = shift;
    print "hello $greeting\n";
}

sub goodbye {
    my $greeting = shift;
    print "goodbye $greeting\n";
}