Remove duplicate value on nested list python

Question

I have a problem here when I want to remove duplicate in a list that has a nested list, how can I remove the duplicate value from list? What I got here from my script, it can remove a duplicate, but the nested list has a different result from what I expect.

This is my script:

# initializing list 
result = []
hasil = []
sam_list = [[11, 17, 11, 13, 13, 15, 16, 11], [4, 7, 11, 34, 4, 7, 11, 6], [1, 6, 11, 13, 13, 4, 1, 6]]

for item in sam_list:
    print("START")
    for x in item:
        print(x, result)
        if x not in result:
            print("NOT IN")
            result.append(x)
    hasil.append(result)

Result:

[[11, 17, 13, 15, 16, 4, 7, 34, 6, 1], [11, 17, 13, 15, 16, 4, 7, 34, 6, 1], [11, 17, 13, 15, 16, 4, 7, 34, 6, 1]]

Expected Result:

[[11, 17, 13, 15, 16], [4, 7, 11, 34, 6], [1, 6, 11, 13, 4]]

Matteo Buffagni · Answer 1 · 2022-07-07T08:59:38.383

1

Almost there, you just have to reset the result list at every step

for item in sam_list:
   print("START")
   for x in item:
      print(x, result)
      if x not in result:
         print("NOT IN")
         result.append(x)
   hasil.append(result)
   result = []

edited Jul 07 '22 at 08:59

answered Jul 07 '22 at 08:44

Matteo Buffagni

312
2
10

Nishant · Accepted Answer · 2022-07-07T08:45:51.533

0

You need to initialize result = [] inside the loop:

sam_list = [[11, 17, 11, 13, 13, 15, 16, 11], [4, 7, 11, 34, 4, 7, 11, 6], [1, 6, 11, 13, 13, 4, 1, 6]]
hasil = []

for item in sam_list:
    result = []
    print("START")
    for x in item:
        print(x, result)
        if x not in result:
            print("NOT IN")
            result.append(x)
    hasil.append(result)

If you don't mind order:

original = [[11, 17, 11, 13, 13, 15, 16, 11], [4, 7, 11, 34, 4, 7, 11, 6], [1, 6, 11, 13, 13, 4, 1, 6]]

[list(set(each)) for each in original]

edited Jul 07 '22 at 08:45

answered Jul 07 '22 at 08:42

Nishant

20,354
18
69
101

Also check https://stackoverflow.com/questions/7961363/removing-duplicates-in-lists for ideas. – Nishant Jul 07 '22 at 08:47

score 0 · Answer 3 · answered Jul 07 '22 at 08:51

You can use set. It automatically removes any duplicates, then convert it to a list again if you want.

sam_list = [[11, 17, 11, 13, 13, 15, 16, 11], [4, 7, 11, 34, 4, 7, 11, 6], [1, 6, 11, 13, 13, 4, 1, 6]]
set1=set(sam_list[0])
set2=set(sam_list[1])
set3=set(sam_list[2])

result = [list(set1),list(set2),list(set3)]
print(result)

the output is: [[11, 13, 15, 16, 17], [34, 4, 6, 7, 11], [1, 4, 6, 11, 13]]

Remove duplicate value on nested list python

3 Answers3