python - Unique only cartesian product of several lists

Question

The following works well for cart_product([1,2,3], [a,b,c], [v]), doesn't it also return duplicate cartesian product, if so, how to get unique cartesian products?

import itertools
def cart_product(*somelists):
    for element in itertools.product(*somelists):
        print element

also this doesn't seem to work when I pass in a list containing lists [ [1,2,3],[a,b,c],[v] ]

Answer 1

1. To get only the unique elements, you can use set notation like this (Note: This doesnt guarantee the order)

   return list({element for element in itertools.product(*somelists)})
   

   or as per Paul Draper's comment we can do it like this

   list(set(itertools.product(*somelists)))
   

   If you want to maintain the order as well

   import itertools
   def cart_product(somelists):
       result, tempSet = [], set()
       for element in itertools.product(*somelists):
           if element not in tempSet:
           tempSet.add(element)
           result.append(element)
       return result
   

2. To make your program work with list of lists, just change the function declaration from

   def cart_product(*somelists):
   

   to

   def cart_product(somelists):