The itertools module also supports computing all combinations of a set of values. When looking at combinations, the order doesn't matter, so there are far fewer combinations than permutations. The number of combinations is often stated as 
. This is the number of ways that we can take combinations of r things at a time from a universe of p items overall.
For example, there are 2,598,960 five-card poker hands. We can actually enumerate all 2 million hands by executing the following command:
hands = list( combinations(tuple(product(range(13), '♠♥♦♣')), 5))
More practically, assume we have a dataset with a number of ...
