# Python | Group summation of a list of tuples

Method: Using ` + operator ` ` Counter () ` + ` + operator `

This the task can be done using the Counter function as it is internally grouped, and the addition operator can be used to specify the functionality of the grouped result.

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 ` # Python3 demo code ` ` # group summation of the list of tuples ` ` # using Counter () + operator & quot; + & quot; ` ` from ` ` collections ` ` import ` ` Counter `   ` # initialize the list of tuples ` ` test_list1 ` ` = ` ` [(` ` 'key1' ` `, ` ` 4 ` `), (` ` 'key3' ` `, ` ` 6 ` `), (` ` 'key2' ` `, ` ` 8 ` `)] ` ` test_list2 ` ` = ` ` [(` ` 'key2' ` `, ` ` 1 ` `), (` ` 'key1' ` `, ` ` 4 ` `), (` `' key3' ` `, ` ` 2 ` `)] `   ` # print original lists ` ` print ` ` (` ` "The original list 1:" ` ` + ` ` str ` ` (test_list1)) ` ` print ` ` (` ` "The original list 2:" ` ` + ` ` str ` ` (test_list2)) `   ` # using Counter () + operator & quot; + & quot; ` ` # group summation of the list of tuples ` ` cumul_1 ` ` = ` ` Counter (` ` dict ` ` (test_list1)) ` ` cumul_2 ` ` = ` ` Counter (` ` dict ` ` (tes t_list2)) ` ` cumul_3 ` ` = ` ` cumul_1 ` ` + ` ` cumul_2 ` ` res ` ` = ` ` list ` ` (cumul_3.items ()) `   ` # print result ` ` print ` ` (` ` "The grouped summation tuple list is:" ` ` + ` ` str ` ` (res)) `
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` ` Output:

` The original list 1: [('key1', 4), (' key3', 6), ('key2', 8 )] The original list 2: [('key2', 1), (' key1', 4), ('key3', 2)] The grouped summation tuple list is: [(' key2', 9), (' key1', 8), ('key3', 8)] `