Delete None values from Python dict

Question

Newbie to Python, so this may seem silly.

I have two dicts:

default = {'a': 'alpha', 'b': 'beta', 'g': 'Gamma'}
user = {'a': 'NewAlpha', 'b': None}

I need to update my defaults with the values that exist in user. But only for those that have a value not equal to None. So I need to get back a new dict:

result = {'a': 'NewAlpha', 'b': 'beta', 'g': 'Gamma'}

Answer 1

result = default.copy()
result.update((k, v) for k, v in user.iteritems() if v is not None)

Answer 2

With the update() method, and some generator expression:

D.update((k, v) for k, v in user.iteritems() if v is not None)