Average of a list of numbers, stored as strings in a Python list

Question

I want to calculate the average value of several lists in python. These lists contain numbers as strings. Empty string isn\'t zero, it means a missing value.

The be

Answer 1

You can discard the square brackets. sum accepts generator expressions, too:

total  = sum(int(n) if n else 0 for n in num)
length = sum(1 if n else 0 for n in num)

And since generators yields the value only when needed, you save the expensive cost of storing a list in the memory. Especially if you're dealing with bigger datas.