Select Code to Download

@last_n = grep { defined $_ } @source[ -$n .. -1 ];

$ perl -wle '@a = 1..3; @b = grep { defined $_ } @a[-4 .. -1]; print "
+<$_>" for @b;'
Modification of non-creatable array value attempted, subscript -4 at -
+e line 1.
...
<1>
<2>
<3>