Need unique nested list from nested list

Question

I have the below nested list:

sample = [['Ban', 'App'], ['Ban', 'Ora'], ['Gra', 'App'], ['Gra', 'Ora'], ['Kiw','App'], ['Kiw', 'Ora'], ['Man', 'Blu'], ['Pin', 'App']]

I need to consider items in each sub-list of the nested list, sample, that don't appear in any other sub-lists.

For example, my output list needs to contain the first element of the nested_list. I need to compare ['Ban', 'App'] with the rest of the list. As "Ban" in element 2 and "App" in element 3 are present in ['Ban', 'App'], we do not consider them. My next output element will is ['Gra', 'Ora'] as these items are not in ['Ban', 'App'].

Now my output is [['Ban', 'App'], ['Gra', 'Ora']] and I have to compare the rest of the nested list with these two elements. My next elements are ['Kiw','App'] and ['Kiw', 'Ora']. As 'App' is in ['Ban', 'App'], and 'Ora' is in ['Gra', 'Ora'], this won't be in the output list.

My output list is still [['Ban', 'App'], ['Gra', 'Ora']]. My next element is ['Man', 'Blu'] and these are brand new items, this will be added in my output list.

My new output list is [['Ban', 'App'], ['Gra', 'Ora'], ['Man', 'Blu']]. The last element is ['Pin', 'App'] and as "App" is in ['Ban', 'App'], we don't consider this item even though "Pin" is a new item.

My final output should be [['Ban', 'App'], ['Gra', 'Ora'], ['Man', 'Blu']].

final_output = [['Ban', 'App'], ['Gra', 'Ora'], ['Man', 'Blu']]

I started with the below code but this doesn't do exactly what I need it to do:

j =0
for i in range(len(sample)):
    #print ("I:", str(i))
    #print ("J" ,str(j))
    i = j
    for j in range(1, len(sample)):
        if sample[i][0] == sample[j][0] or sample[i][0] == sample[j][1] or sample[i][1] == sample[j][0] or sample[i][1] == sample[j][1]:
            pass
        else:
            print (sample[i], sample[j])
            #print (j)
            i = j
            break

Answer 1

I would keep a set that keeps track of items already seen and only add the pair to the final list if there is no intersection with that set.

st = set()
final_output = []
for pair in sample:
    if not st.intersection(pair):
        final_output.append(pair)
        st.update(pair)

print(final_output)
# [['Ban', 'App'], ['Gra', 'Ora'], ['Man', 'Blu']]