Python: Sum values in a dictionary based on condition

Question

I have a dictionary that has Key:Values.

The values are integers. I would like to get a sum of the values based on a condition...say all values > 0 (i.e).

I've tried few variations, but nothing seems to work unfortunately.

See http://stackoverflow.com/questions/11692613/python-sum-values-in-dictionary — Mihai8, Feb 21 '13 at 23:39

RocketDonkey · Answer 1 · 2013-02-21T23:44:34.957

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Try using the values method on the dictionary (which returns a generator in Python 3.x), iterating through each value and summing if it is greater than 0 (or whatever your condition is):

In [1]: d = {'one': 1, 'two': 2, 'twenty': 20, 'negative 4': -4}

In [2]: sum(v for v in d.values() if v > 0)
Out[2]: 23

edited Feb 21 '13 at 23:44

answered Feb 21 '13 at 23:38

RocketDonkey

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Wow, that may be the best example I've seen of a concise explanation in English that maps to a generator expression in such an obvious way that you don't even need to say that's what you're doing. Wish I could give more than +1. – abarnert Feb 22 '13 at 00:51
@abarnert Coming from you that is quite a compliment, thanks :) – RocketDonkey Feb 22 '13 at 02:49

score 1 · Answer 2 · edited Feb 21 '13 at 23:39

1

>>> a = {'a' : 5, 'b': 8}
>>> sum(value for _, value in a.items() if value > 0)

edited Feb 21 '13 at 23:39

mechanical_meat

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answered Feb 21 '13 at 23:37

Damgaard

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Python: Sum values in a dictionary based on condition

2 Answers2