my @x; $x[9] = 1; print "$#x ", scalar(@x), $/; print exists $x[2] ? 1 : 0, $/; print defined $x[2] ? 1 : 0, $/; $x[2] = undef; print exists $x[2] ? 1 : 0, $/; print defined $x[2] ? 1 : 0, $/; ---- 9 10 0 0 1 0