#!/usr/bin/python
# Ivan Novick
# Dec-25, 2007
# demonstrate set operators

# create 4 sets
# each set is the numbers from 1-50 that are divisible by 2,3,4,5 respectively

twos = set([2,4,6,8,10,12,14,16,18,20,22,24,26,28,30,32,34,36,38,40,42,44,46,48,50])
threes = set([3,6,9,12,15,18,21,24,27,30,33,36,39,42,45,48])
fours = set([4,8,12,16,20,24,28,32,36,40,44,48])
fives = set([5,10,15,20,25,30,35,40,45,50])

# union of fours and fives
a = fours | fives
print "union of 4s and 5s: ", a

# intersection of twos and threes
b = twos & threes
print "intersection of 2s and 3s: ", b

# difference between fours and fives
c = fours - fives
print "items in 4s but not 5s: ", c

# items in twos or fours but not both
d = twos ^ fours
print "items in 2s or 4s but not both: ", d