>>> lsts = [
... [1,2,3,4],
... [1,2,3,5],
... [2,2,3,4]]
>>>
>>> results = []
>>> for col in zip(*lsts):
... if not all(x == col[0] for x in col):
... results.append('x')
... else:
... results.append(col[0])
...
>>> results
['x', 2, 3, 'x']
Замените 'x'
нужной переменной.