Sum / Average an attribute of a list of objects

Question

Lets say I have class C which has attribute a.

What is the best way to get the sum of a from a list of C in Python?

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I've tried the following code, but I know that's not the right way to do it:

for c in c_list:
    total += c.a

Answer 1

Use a generator expression:

sum(c.a for c in c_list)