Why do I get a MemoryError with itertools.product?

Question

I would expect the following snippet to give me an iterator yielding pairs from the Cartesian product of the two input iterables:

$ python
Python 2.7.1+ (r27         


        

Answer 1

I think the problem could be that xrange returns its own special sort of object, which is not a normal iterable.

xrange is implemented in such a way (as are lists) that you can iterate over the object many times, while you can iterate over a normal generator object only once. So perhaps something from this functionality is responsible for the memory error.