Accessing elements of itertools product in a for loop

Question

I have a list of list being the result of appending some other results from itertools product. What I want is to be able to access each element of the lists in the list of lists

Answer 1

itertools.product itself returns an object you can iterate over. For example:

>>> from itertools import product
>>> animal = ['dog','cat']
>>> number = [5,45,8,9]
>>> color = ['yellow','blue','black']
>>> myProduct = product(animal, number, color)
>>> for p in myProduct:
...     print p
...     
('dog', 5, 'yellow')
('dog', 5, 'blue')
('dog', 5, 'black')
[...]
('cat', 9, 'blue')
('cat', 9, 'black')

After this, myProduct is exhausted (out of elements to yield) and so if you loop again you won't get anything:

>>> for p in myProduct:
...     print p
...     
>>> 

If you want to materialize myProduct into a list, you can do that:

>>> myProduct = list(product(animal, number, color))
>>> len(myProduct)
24
>>> myProduct[7]
('dog', 8, 'blue')

By appending the product object itself to a list, you're not getting the list iterating it would produce, only the object.

>>> myProduct = product(animal, number, color)
>>> myProduct
<itertools.product object at 0x8e3ce3c>

If you want, you can store this object somewhere, and get elements from it the same way:

>>> some_list = [myProduct, myProduct]
>>> next(some_list[0])
('dog', 5, 'yellow')
>>> next(some_list[1])
('dog', 5, 'blue')
>>> next(some_list[1])
('dog', 5, 'black')
>>> next(some_list[0])
('dog', 45, 'yellow')

but here I don't think that's what you're looking for.

Answer 2

Reading your post many times, I think you are interested in this syntax:

for animal, number, color in ...:

It allows you to access the elements from the inner lists.

import itertools
animals = ['dog', 'cat']
numbers = [5, 45, 8, 9]
colors = ['yellow', 'blue', 'black']
for animal, number, color in itertools.product(animals, numbers, colors):
    print "Animal is {0}, number is {1}, and color is {2}".format(animal, number, color)

See this running on ideone

EDIT: Reading your comments in the other thread, I guess(?) you're interested in iterating over the inner tuples. You don't have to convert them to a list, you can simply iterate over them.

import itertools
animals = ['dog', 'cat']
numbers = [5, 45, 8, 9]
colors = ['yellow', 'blue', 'black']
for triplet in itertools.product(animals, numbers, colors):
    for element in triplet:
        print element

Demo on ideone

EDIT 2: You can try that approach for your score thing.

import itertools
animals = ['dog', 'cat']
numbers = [5, 45, 8, 9]
colors = ['yellow', 'blue', 'black']
general_list = ['horse', 'blue', 'dog', 45]

def give_score(element):
    return 1 if element in general_list else 0

for triplet in itertools.product(animals, numbers, colors):
    print sum([give_score(element) for element in triplet])

Demo here