Unique sublists in Python

I have a list D containing many sublists. I want to identify unique sublists and remove the repeating ones. By unique, I mean all the elements are the same irrespective of the locations of specific elements. But I am getting an error. I present the expected output.

D=[[0, 2, 3, 5], [1, 3, 4, 6], [2, 0, 3, 5], [4, 1, 3, 6]]

for i in range(0,len(D)): 
    E=D[i].unique
    print(E)

The error is

in <module>
    E=D[i].unique

AttributeError: 'list' object has no attribute 'unique'

The expected output is

[[0, 2, 3, 5], [1, 3, 4, 6]]

You haven't defined what you mean by "unique" precisely enough. If there are no repeats in the sublists, then you can do something like:

def unique_sublists(data):
    seen = set()
    result = []
    for sub in data:
        uniq = frozenset(sub)
        if uniq not in seen:
            result.append(sub)
            seen.add(uniq)
    return result

If there can be repeats, you might need something like:

def unique_sublists(data):
    from collections import Counter
    seen = set()
    result = []
    for sub in data:
        uniq = frozenset(Counter(sub).items())
        if uniq not in seen:
            result.append(sub)
            seen.add(uniq)
    return result

You can use set to get unique items. If you don't care if order is changed, you can use list comprehension that sorts each sublist, converts it to a tuple so that it can be hashed, and then finally convert it to a set to remove duplicates.

unique = set(tuple(sorted(a)) for a in D)
# convert back to lists
unique = [list(a) for a in unique]

If you do care about order, you can do a similar thing except make a dictionary to get the original sublist.

unique = dict(zip([tuple(sorted(a)) for a in D], D)).values()
# convert back to lists
unique = [list(a) for a in unique]

There are multiple ways of doing this, I will add the two I came up with:

1. Using map to order the lists and then set to remove the duplicated ones.

list(set(map(lambda x: tuple(sorted(x)), D)))

2. Here using a temporary list to add only if the items have not been added yet.

   out = []
   for i in map(sorted, D):
       if i not in out: out.append(i)
   
   
   

There is no method named 'unique' for Python lists hence the error.
To identify unique sublists, you can convert the sublists to tuples, create a set of tuples to remove duplicates, and then convert the tuples back to lists. You could solve this as below:

D = [[0, 2, 3, 5], [1, 3, 4, 6], [2, 0, 3, 5], [4, 1, 3, 6]]
#sort the sublist elements (I found this to be able to eliminate them by a set method below) that's if element order doesn't matter in your case
unique_tuples = set(tuple(sorted(sublist)) for sublist in D)

unique_sublists = [list(t) for t in unique_tuples]
print(unique_sublists)
[[0, 2, 3, 5], [1, 3, 4, 6]]

This is working.

D = [[0, 2, 3, 5], [1, 3, 4, 6], [2, 0, 3, 5], [4, 1, 3, 6]]

unique_sublists = []
for sublist in D:
    if set(sublist) not in [set(x) for x in unique_sublists]:
        unique_sublists.append(sublist)

print(unique_sublists)