A python function for removing sublist from nested list

Question

I want to remove all occurrences of a list from list of lists. By that I mean I want to filter out all the occurrences of a given list. E.g.

list = [[1,2,3], [3,2,1] ,[4,2,5],[1,2,3]]
list.removeList([1,2,3])
list=[[3,2,1],[4,2,5]]

I was thinking of using a filter or .remove() but it is giving me error. And for the filter I don't know what approach I should start with

score 1 · Answer 1 · answered Nov 27 '20 at 22:24

1

Use a list comprehension

l = [sublist for sublist in l if sublist != [1, 2, 3]]

answered Nov 27 '20 at 22:24

Barmar

ombk · Answer 2 · 2020-11-27T22:24:06.163

0

list1 = [[1,2,3], [3,2,1] ,[4,2,5],[1,2,3]]
list2= list1

for i in list1:
    if i==[1,2,3]:
        list2.remove(i)

With append

list1 = [[1,2,3], [3,2,1] ,[4,2,5],[1,2,3]]
list2= []

for i in list1:
    if i!=[1,2,3]:
        list2.append(i)

edited Nov 27 '20 at 22:24

answered Nov 27 '20 at 22:23

ombk

1

You shouldn't modify a list that you're iterating over. – Barmar Nov 27 '20 at 22:23
@Barmar explain what you mean – ombk Nov 27 '20 at 22:25
`list2` is a reference to the same list as `list1`, so you're calling `remove()` on the same list that you're iterating over with `for i in list1:`. – Barmar Nov 27 '20 at 22:25
See https://stackoverflow.com/questions/6260089/strange-result-when-removing-item-from-a-list – Barmar Nov 27 '20 at 22:26

2 Answers2