Python: Find identical items in multiple lists

Question

I have a list of an arbitrary number of lists, for instance:

[[1,2,3], [3,4,5], [5,6,7], [7,8,9]]

Now I would like a list containing all elements that are present in more than one list:

[3,5,7]

How would I do that?

Thanks!

Answer 1

I am still learning but would like to share my answer.

num_list1 = ['3', '6', '5', '8', '33', '12', '7', '4', '72', '2', '42', '13']
num_list2 = ['3', '6', '13', '5', '7', '89', '12', '3', '33', '34', '1', '344', '42']

result = [int(num) for num in num_list1 if num in num_list2)
print(result)

This prints:

[3, 6, 5, 33, 12, 7, 42, 13]

Comparing all elements in both lists and creating a new list with similar elements. And turning them into integers.