Proper way to remove keys in dictionary with None values in Python

Question

What is the proper way to remove keys from a dictionary with value == None in Python?

Answer 1

Generally, you'll create a new dict constructed from filtering the old one. dictionary comprehensions are great for this sort of thing:

{k: v for k, v in original.items() if v is not None}

If you must update the original dict, you can do it like this ...

filtered = {k: v for k, v in original.items() if v is not None}
original.clear()
original.update(filtered)

This is probably the most "clean" way to remove them in-place that I can think of (it isn't safe to modify a dict while you're iterating over it)

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^{Use original.iteritems() on python2.x}