Sets

knights = { “Galahad”, “Lancelot”, “Arthur”}

# create a new empty set
Example = set()
# check methods
dir(Example)
# Use of methods
help(Example.add)

# A set can have elements of any type
Example.add(42)
Example.add(True)
Example.add(“Hi”)
# order and types does not matter
Example.add(42)
# does not duplicate
Example.remove(True)
# Error if not in set
Example.discard(43)
# Does not crash

odds = set([1, 3, 5, 7, 9])
evens = set([2, 4, 6, 8])
primes = set([2, 3, 5, 7])

odds.union(evens)
evens.union(odds)
odds.intersection(primes)
odds.intersection(evens’ # == set()
2 in primes # True
5 not in primes # False