Python: shortest way to compute cartesian power of

问题:

This question already has an answer here:

• Get the cartesian product of a series of lists? 11 answers

Suppose we have a list L. The cartesian product L x L could be computed like this:

product = [(a,b) for a in L for b in L]

How can the cartesian power L x L x L x ... x L (n times, for a given n) be computed, in a short and efficient way?

回答1:

Using itertools.product():

product = itertools.product(L, repeat=n)

where product is now a iterable; call list(product) if you want to materialize that to a full list:

>>> from itertools import product
>>> list(product(range(3), repeat=2))
[(0, 0), (0, 1), (0, 2), (1, 0), (1, 1), (1, 2), (2, 0), (2, 1), (2, 2)]