Removing duplicity of items in list of lists based on a specific index #Python

Question

I have the following lists:

lista = [1,2,3,5]
listb = [1,5,2,6]
listc = [3,5,1,6]
mainList = [lista,listb,listc]

I'd like to remove listb from mainList since it contains the same element as lista at index position[0].

Kinda like the code below, however, applied to every list contained in mainList. basically, remove all lists with index 0 duplicity while maintaining the first one.

if lista[0] == listb[0]:
    mainList.remove(listb)

#But to include duplicity in for all elements in mainList.

Anybody? Thanks in advance!

Answer 1

You can use the code below-

lista = [1,2,3,5]
listb = [1,5,2,6]
listc = [3,5,1,6]
mainList = [lista,listb,listc]
ml_final = mainList.copy()    #make a copy of the main list, this would be the final list

first_ele = []     #make empty list where first elements of all the lists are added
for i in range(len(mainList)):
  temp = mainList[i][0]
  if temp in first_ele:
    ml_final.pop(i)
  else:
    first_ele.append(temp)

#output
print(ml_list)
#[[1, 2, 3, 5], [3, 5, 1, 6]]