Current Perl documentation can be found at perldoc.perl.org.

Here is our local, out-dated (pre-5.6) version:

Use for/foreach:

    for (@lines) {
        s/foo/bar/;     # change that word
        y/XZ/ZX/;       # swap those letters
    }

Here's another; let's compute spherical volumes:

    for (@volumes = @radii) {   # @volumes has changed parts
        $_ **= 3;
        $_ *= (4/3) * 3.14159;  # this will be constant folded
    }

If you want to do the same thing to modify the values of the hash, you may not use the values function, oddly enough. You need a slice:

    for $orbit ( @orbits{keys %orbits} ) {
        ($orbit **= 3) *= (4/3) * 3.14159; 
    }