How do I use __getitem__ and __iter__ and return values from a dictionary?

Question

I have an object with a dictionary that I want to access via __getitem__ as well as iterate over (values only, keys don\'t matter) but am not sure how to do it.

Answer 1

You can return an iterator from your inner data:

class Library (object):
  ...
  def __iter__(self):
    return self.books.itervalues()

itervalues() returns an iterator to the values of the dictionary.

If you want more control, you can make __iter__ a generator function

class Library (object):
  ...
  def __iter__(self):
    for title in self.books:
      yield self.books[title]

in this case, this generator yields the exact same as the iterator in the first example.