python - Remove partially duplicate tuples from list of tuples

Question

I have a list of tuples and need to delete tuples if its 1st item is matching with 1st item of other tuples in the list. 3rd item may or may not be the same, so I cannot use set (I have seen this question - Grab unique tuples in python list, irrespective of order and this is not same as my issue)

For eg if I got a as:

[(0, 13, 'order1'), (14, 27, 'order2'), (14, 27, 'order2.1'), 
 (0, 13, 'order1'), (28, 41, 'order3')]

I want the output as:

[(14, 27, 'order2'), (0, 13, 'order1'), (28, 41, 'order3')]

I am getting the desired output using below code.

for e, i in enumerate(a):
    r = [True if i[0] == k[0] and e != j else False for j, k in enumerate(a)]
    if any(r):
        a.pop(e)
pprint(a)

Is there a better or more pythonic way to achieve the same?

Answer 1

The usual way is keying a dict off whatever you want to dedupe by, for example:

>>> a = [(0, 13, 'order1'), (14, 27, 'order2'), (14, 27, 'order2.1'), (0, 13, 'order1'), (28, 41, 'order3')] 
>>> print(*{tup[:2]: tup for tup in a}.values()) 
(0, 13, 'order1') (14, 27, 'order2.1') (28, 41, 'order3')

This is O(n) time complexity, superior to O(n log n) groupby based approaches.