Sets

Sets are lists with no duplicate entries.
Since the rest of the sentence uses words which are already in the set, they are not inserted twice.

print(set("I want it Pronto and I am late".split()))

Sets are huge importance. When look for differences and intersections between other sets. For example, say you have a list of participants in events A and B:

a = set(["or", "ni", "car"])
print(a)
b = set(["oui", "non"])
print(b)

To find out which members attended both events, you may use the "intersection" method:

a = set(["or", "ni", "car"])

b = set(["oui", "non"])


print(a.intersection(b))
print(b.intersection(a))

To find out which members attended only one of the events, use the "symmetric_difference" method:

a = set(["or", "ni", "car"])

b = set(["oui", "non"])


print(a.symmetric_difference(b))
print(b.symmetric_difference(a))

To find out which members attended only one event and not the other, use the "difference" method:
To receive a list of all participants, use the "union" method:

a = set(["or", "ni", "car"])
b = set(["oui", "non"])

print(a.union(b))