my $x = 100; my @y = (10, 20, 30); foreach ($x, @y) { $_ *= 2; } local $" = ", "; print "\$x = $x\n\@y = (@y)\n"; #### # or: foreach my $n ($x, @y) { $n *= 2; } #### map { $_ *= 2 } $x, @y; #### grep { $_ *= 2 } $x, @y; #### sub double { foreach(@_) { $_ *= 2; } } double($x, @y);