Question

I have a list of tuples:

lst = [('a','b'), ('c', 'b'), ('a', 'd'), ('e','f'), ('a', 'b')]

I want the following output list:

output = [('a','b'), ('e','f')]

i.e I want to compare the elements of first tuple with remaining tuples and remove the tuple which contains either one or more duplicate elements.

My attempt:

I was thinking of using for loops, but that wont be feasible once i have very large list. I browsed through following posts but could not get the right solution:

Removing duplicates members from a list of tuples
How do you remove duplicates from a list in whilst preserving order?

If somebody could guide me the right direction, it will be very helpful. Thanks!

Answer 1

Assuming that you want “duplicates” of all elements to be suppressed, and not just the first one, you could use:

lst = [('a','b'), ('c', 'b'), ('a', 'd'), ('e','f'), ('a', 'b')]

def merge(x):
    s = set()
    for i in x:
        if not s.intersection(i):
            yield i
            s.update(i)

gives

>>> list(merge(lst))
[('a', 'b'), ('e', 'f')]
>>> list(merge([('a', 'b'), ('c', 'd'), ('c', 'e')]))
[('a', 'b'), ('c', 'd')]
>>> list(merge([('a', 'b'), ('a', 'c'), ('c', 'd')]))
[('a', 'b'), ('c', 'd')]