#!/usr/bin/perl
use strict;
use warnings;<P>

my @names = qw (Tizio Caio Sempronio);<P>

show_indexed();<P>

my @selected = select_by_index();
print "First choice:\n--->",(join "\n--->",@selected),"\n";<P>

## and then..
push @names,'stevek1974';
show_indexed();<P>

my @selected_bis = select_by_index();
print "Second choice:\n--->",(join "\n--->",@selected_bis),"\n";<P>

################################################################################
sub show_indexed {
    print "\nChoice one or more name, using their index:\n";
    my $index = 0;
    foreach my $name (@names){
      print  "[$index]\t$name\n";
      $index++;
    }
    print "\n";
}
################################################################################
sub select_by_index {
    my $in = <STDIN>;
    chomp $in;
    # checks are needed in thi case..
    unless ($in=~/^[\d,]+$/){warn "WARNING: invalid input!\n";select_by_index()}<P>

    my @choice = @names[split /,/, $in];#thanks to tye and choroba: i used @names[eval $in]
    # more checks are better..
    unless (defined $choice[0]){
            warn "WARNING: probably you need to check that input numbers are
                  valid for the current array!\n";
            select_by_index()
    }
    return @choice;
}