Eliminate duplicated sublists when sublists are uneven in Python

Question

Consider the list:

    test = [['B', [4, 5, 6]], ['C', [7, 8, 9]], ['C', [7, 8, 9]]]

I want the return to be: [['B', [4, 5, 6]], ['C', [7, 8, 9]]]

I am able to get the result using loop structures:

    new_test = []

    for sub in test:
            if sub not in new_test:
                    new_test.append(sub)    
    
    #[['B', [4, 5, 6]], ['C', [7, 8, 9]]]

I've ran some tests with the popular set-tuple method, but it doesn't work here because sublists are uneven:

    set(tuple(x) for x in test)

I've tried with the original test list and also tried:

    test = [[4, [5, 6],[7, 8], 9],[7, 8, 9]]
    

Both return same error:

Error: set(tuple(x) for x in test)

TypeError: unhashable type: 'list'

Is there any other way to get rid off duplicates without "for loops"? I have no big issues with loops, I just want to explore other types of coding in Python. The order of the sublists are not important.

Answer 1

If the equal sublists are consecutive as in the example, you can use itertools.groupby here:

from itertools import groupby

[next(v) for k,v in groupby(test)]
# [['B', [4, 5, 6]], ['C', [7, 8, 9]]]