How to remove similar list from a list. how to remove duplicates from the list

Question

index=[[25, 0], [25, 1], [25, 0], [25, 4], [25, 1], [25, 4], [56, 2], [56, 3]]
for x in range(0,len(index)):
    for y in range(x+1,len(index)):
        if index[x][-1]==index[y][-1]:
            index.remove(index[y])
print(index)

Got the following error:

 if index[x][-1]==index[y][-1]: IndexError: list index out of range

it would be easier if you convert these nested `lists` into a `tuple` and then use `set`. — Vishal Singh, Dec 30 '20 at 08:18
Now is a good time to learn the practices of basic debugging. Your post should include your trace of `x, y,` and `index` on each loop iteration, especially just before the point of failure. You also should not ask how to remove duplicates, as that is a straightforward lookup. Please repeat [on topic](https://stackoverflow.com/help/on-topic) and [how to ask](https://stackoverflow.com/help/how-to-ask) from the [intro tour](https://stackoverflow.com/tour). You haven't yet done the expected research. — Prune, Dec 30 '20 at 08:24
`newlist = [x for i,x in enumerate(mylist) if x not in mylist[:i]]` will do the trick — Joe Ferndz, Dec 30 '20 at 08:25

score 1 · Accepted Answer · answered Dec 30 '20 at 08:15

You are looping over a list and deleting the same list simultaneously .. It ran out of index with which the loop was started. Make a copy of list and then run over it.

Slightly edited code.

index=[[25, 0], [25, 1], [25, 0], [25, 4], [25, 1], [25, 4], [56, 2], [56, 3]]
index_for_loop = index.copy()
for x in range(0,len(index_for_loop)):
    for y in range(x+1,len(index_for_loop)):
        if index_for_loop[x]==index_for_loop[y]:
            index.remove(index_for_loop[y])
print(index)

Gives output

[[25, 0], [25, 1], [25, 4], [56, 2], [56, 3]]

score 1 · Answer 2 · answered Dec 30 '20 at 08:17

1

One-liner:

index = list(map(list, (set(tuple(a) for a in index))))

gives

[[25, 4], [25, 0], [56, 3], [56, 2], [25, 1]]

Lists are unhashable in Python, hence you need to convert them to tuple first.

answered Dec 30 '20 at 08:17

Jarvis

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score 0 · Answer 3 · answered Dec 30 '20 at 08:23

You can try the following

index = [[25, 0], [25, 1], [25, 0], [25, 4], [25, 1], [25, 4], [56, 2], [56, 3]]

lst = []

for i in range(len(index)):
    if index[i] not in lst:
        lst += [index[i]]

print(lst)
>>> [[25, 0], [25, 1], [25, 4], [56, 2], [56, 3]]

How to remove similar list from a list. how to remove duplicates from the list

3 Answers3