$ perl -wle'
my %h = (a => 23, b => 24, c => 25);
print "while";
while (my ($k, $v) = each %h) {
  print "$k => $v";
}
print "for";
for (my ($k, $v) = each %h) {
  print "$k => $v";
}
'
while
c => 25
a => 23
b => 24
for
c => 25
c => 25