# Python – Paired elements grouping

• Last Updated : 02 Jun, 2020

Sometimes, while working with Python records, we can have a problem in which we have tuple list as data and we desire to group all the elements which form a chain, i.e are indirect pairs of each other or are connected components. This kind of problem can occur in domains such as competitive programming. Let’s discuss certain way in which this task can be performed.

Input : test_list = [(1, 3), (4, 5)]
Output : []

Input : test_list = [(1, 3), (3, 5)]
Output : [{1, 3, 5}]

Method : Using loop + `set() + intersection()`
The combination of above functionalities can be used to solve this problem. In this, we iterate for all the elements and then for all the elements occurring after that in nested loop. The intersection of elements is performed, and if, any element if found similar, i.e size >= 0, then tuple is merged in similar chain.

 `# Python3 code to demonstrate working of ``# Paired elements grouping``# Using loop + set() + intersection()`` ` `# initializing list``test_list ``=` `[(``1``, ``3``), (``4``, ``5``), (``1``, ``7``), (``3``, ``4``), (``7``, ``8``)]`` ` `# printing original list``print``(``"The original list is : "` `+` `str``(test_list))`` ` `# Paired elements grouping``# Using loop + set() + intersection()``res ``=` `[]``for` `sub ``in` `test_list:``    ``idx ``=` `test_list.index(sub)``    ``sub_list ``=` `test_list[idx ``+` `1``:]``    ``if` `idx <``=` `len``(test_list) ``-` `2``:``        ``for` `ele ``in` `sub_list:``            ``intrsct ``=` `set``(sub).intersection(``set``(ele))``            ``if` `len``(intrsct) > ``0``:``                ``res.append(``set``(sub ``+` `ele))``                 ` `# printing result ``print``(``"The grouped list : "` `+` `str``(res)) `
Output :
```The original list is : [(1, 3), (4, 5), (1, 7), (3, 4), (7, 8)]
The grouped list : [{1, 3, 7}, {1, 3, 4}, {3, 4, 5}, {8, 1, 7}]
```
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