9.5 Generating all combinations
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:
>>> from itertools import combinations, product
>>> hands = list(
... combinations(
... tuple(
... product(range(13), ’♠♡♢♣’)
... ), 5
... ) ...
