In a list of list objects, how do i compare each list object with all other list objects?

Question

I have a list with multiple list objects in it, I wish to compare each inner list to all other inner lists in the outer list object and if a match is found, print it out.

I have already tried looping through each object in the list and compare it to all other objects but I always match the one I start with.

My example list is this:

list_of_lists = [
    [1, 11, 17, 21, 33, 34],
    [4, 6, 10, 18, 22, 25],
    [1, 15, 20, 22, 23, 31],
    [3, 5, 7, 18, 23, 27],
    [3, 22, 24, 25, 28, 37],
    [7, 11, 12, 25, 28, 31],
    [1, 11, 17, 21, 33, 34],
    ...
]

Note that list_of_lists[0] matches list_of_lists[6], which I wish to match in this example.

The expected result is a loop that goes through each list object and compares it to all other objects, if there's a match - print it out.

Answer 1

You could do something like this:

list_of_lists = [
    [1, 11, 17, 21, 33, 34],
    [4, 6, 10, 18, 22, 25],
    [1, 15, 20, 22, 23, 31],
    [3, 5, 7, 18, 23, 27],
    [3, 22, 24, 25, 28, 37],
    [7, 11, 12, 25, 28, 31],
    [1, 11, 17, 21, 33, 34],
]

for i in range(len(list_of_lists)):
    for j in range(len(list_of_lists)):
        # If you're checking the row against itself, skip it.
        if i == j:
            break
        # Otherwise, if two different lists are matching, print it out.
        if list_of_lists[i] == list_of_lists[j]:
            print(list_of_lists[i])

This outputs:

[1, 11, 17, 21, 33, 34]