CODEWITHSUNDEEP
pythonlistduplicatesnested-lists
Raspel
Raspel

Reputation: 383

Remove duplicates from list of lists

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?

Upvotes: 0

Views: 3832

Answers (2)

João Paulo
João Paulo

Reputation: 6670

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]]

Upvotes: 1

TigerhawkT3
TigerhawkT3

Reputation: 49320

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)

Upvotes: 6

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