DB<129> scalar %empty
 => 0

##</code><code>##

  DB<100> $h{$_}=$_ for 1..5e6

  DB<101> $t=time; %h2=%h; print time-$t;
124
  DB<102> $t=time; ($k)=%h; print time-$t;
19
  DB<103> use Time::HiRes qw(time)

  DB<104> $t=time; ($k)=each %h; print time-$t;
7.70092010498047e-05