Testing all combinations in Python

Question

I have two sets of options:

optionList1 = [a1,a2,a3,...,an]
optionList2 = [b1,b2,b3,...,bn]

The number of elements in the optionlists are not necessarily equal and I have to choose from the first optionlist twice. How do I ensure that I have tried every combination of 2 options from the first list and one from the second list. An example selection set below...

selectedOptions = [an1,an2,bn]

Answer 1

Combine product and permutations from itertools assuming you don't want duplicates from the first list:

>>> from itertools import product,permutations
>>> o1 = 'a1 a2 a3'.split()
>>> o2 = 'b1 b2 b3'.split()
>>> for (a,b),c in product(permutations(o1,2),o2):
...     print a,b,c
... 
a1 a2 b1
a1 a2 b2
a1 a2 b3
a1 a3 b1
a1 a3 b2
a1 a3 b3
a2 a1 b1
a2 a1 b2
a2 a1 b3
a2 a3 b1
a2 a3 b2
a2 a3 b3
a3 a1 b1
a3 a1 b2
a3 a1 b3
a3 a2 b1
a3 a2 b2
a3 a2 b3