Be aware that each keeps state, so adding or deleting elements in an each loop is not the greatest of ideas. However, your pattern of usage seems to be supported, though I wouldn't recommend it.

Quote from perldoc -f each

If you add or delete elements of a hash while you're iterating over it, you may get entries skipped or duplicated, so don't. Exception: It is always safe to delete the item most recently returned by "each()", which means that the following code will work:

while (($key, $value) = each %hash) {
  print $key, "\n";
  delete $hash{$key};   # This is safe
}
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