Python – Tuple List intersection (Order irrespective)

Given list of tuples, perform tuple intersection of elements irrespective of their order.

Input : test_list1 = [(3, 4), (5, 6)], test_list2 = [(5, 4), (4, 3)] 
Output : {(3, 4)} 
Explanation : (3, 4) and (4, 3) are common, hence intersection ( order irrespective).

Input : test_list1 = [(3, 4), (5, 6)], test_list2 = [(5, 4), (4, 5)] 
Output : set() 
Explanation : No intersecting element present. 
 

Method #1 : Using sorted() + set() + & operator + list comprehension 
The combination of above functions can be used to solve this problem. In this, we sort the tuples, and perform intersection using & operator. 

The original list 1 is : [(3, 4), (5, 6), (9, 10), (4, 5)]
The original list 2 is : [(5, 4), (3, 4), (6, 5), (9, 11)]
List after intersection : {(4, 5), (3, 4), (5, 6)}

Method #2 : Using list comprehension + map() + frozenset() + & operator 
The combination of above functions can be used to perform this task. In this, we perform the task of conversion of innercontainers to sets, which orders it, and performs the intersection. Frozenset is used as its hashable, and map() requires hashable data type as argument.

The original list 1 is : [(3, 4), (5, 6), (9, 10), (4, 5)]
The original list 2 is : [(5, 4), (3, 4), (6, 5), (9, 11)]
List after intersection : {frozenset({4, 5}), frozenset({5, 6}), frozenset({3, 4})}