funnel.py

prop1 = lambda n : n % 2 == 0

prop2 = lambda n : n % 3 == 0

prop3 = lambda n : n % 5 == 0

inputs = list(range(1, 1000))

print('Funnel 1')

print('inputs:', len(inputs))
phase1 = list(filter(prop1, inputs))
print('After first funnel(n % 2):', len(phase1))
phase2 = list(filter(prop2, phase1))
print('After second funnel(n % 3):', len(phase2))
phase3 = list(filter(prop3, phase2))
print('After third funnel(n % 5):', len(phase3))

print('Utility Rate:', round(len(phase3) / len(inputs) * 100, 2), '%')


print('Funnel 2')

prop21 = lambda n : n % 2 == 0 \
                or (n % 3 == 0 and n > 600) \
                or (n % 5 == 0 and n > 600)

print('inputs:', len(inputs))
phase21 = list(filter(prop21, inputs))
print('After first funnel(n % 2):', len(phase21))
phase22 = list(filter(prop2, phase21))
print('After second funnel(n % 3):', len(phase22))
phase23 = list(filter(prop3, phase22))
print('After third funnel(n % 5):', len(phase23))

print('Utility Rate:', round(len(phase23) / len(inputs) * 100, 2), '%')

print('Utility Gain:', round((len(phase23) / len(phase3) - 1) * 100, 2), '%')


# Funnel 1
# inputs: 999
# After first funnel(n % 2): 499
# After second funnel(n % 3): 166
# After third funnel(n % 5): 33
# Utility Rate: 3.3 %
# Funnel 2
# inputs: 999
# After first funnel(n % 2): 593
# After second funnel(n % 3): 233
# After third funnel(n % 5): 46
# Utility Rate: 4.6 %
# Utility Gain: 39.39 %