gini.py

pop = [1.0,2.0,3.0]

#total = reduce(lambda x,y: x + y, pop) - no lambdas for me
total = sum(pop)
# cummulative = reduce(lambda x,(i,y): x + y * (len(pop) - i - 1),enumerate(pop)) - doesn't work cuz python
cummulative = 0

for i,x in enumerate(pop):
    cummulative += x * (len(pop) - i - 1)
    
area = (cummulative/total + 0.5) / len(pop)
gini = (2 * (0.5 - area))

print gini