compute mean in python for a generator

Question

I\'m doing some statistics work, I have a (large) collection of random numbers to compute the mean of, I\'d like to work with generators, because I just need to compute the

Answer 1

You can use reduce without knowing the size of the array:

from itertools import izip, count
reduce(lambda c,i: (c*(i[1]-1) + float(i[0]))/i[1], izip(values,count(1)),0)