从列表列表中删除重复项

Question

I have a list containing ~300 lists, however some of them are duplicates and I would like to remove them. I've tried:

cleanlist = [cleanlist.append(x) for x in oldlist if x not in cleanlist]

but it keeps throwing RuntimeError: maximum recursion depth exceeded in comparison at me. I tried sys.setrecursionlimit(1500) but that didn't help.

What's a better way to do this?

Answer 1

You're adding a bunch of stuff to cleanlist based on whether it's in cleanlist (which doesn't exist yet), and then saving the value returned from the append() operation (which is None ) to cleanlist . It will not end well.

A better way to do this is probably with an old-fashioned loop construct:

cleanlist = []
for x in oldlist:
    if x not in cleanlist:
        cleanlist.append(x)

Answer 2

A crazy solution. Maybe It helps:

oldlist = [[1,2,3], [1,2,3], [4,5,6], [7,8], [7,8]]
cleanlist = set(tuple(x) for x in oldlist)
print(list(cleanlist))

>>> [(7, 8), (4, 5, 6), (1, 2, 3)]

For a list of lists, use this:

cleanlist = [list(item) for item in set(tuple(x) for x in oldlist)]
>>> [[7, 8], [4, 5, 6], [1, 2, 3]]