Python | Sort tuple list on basis of difference of elements

• Last Updated : 11 May, 2020

Sometimes, while working with data, we can have a problem of sorting them. There are many types of basis on which sorting can be performed. But this article discusses sorting on basis of difference of both elements of pair. Let’s discuss certain ways in which this can be done.

Method #1 : Using sorted() + lambda
The combination of above functionalities can be used to solve this problem. In this, sorting is performed by sorted() and lambda function is fed as key to perform desired sorting.

 # Python3 code to demonstrate working of# Sort tuple list on basis of difference of elements# using sorted() + lambda  # initialize list test_list = [(1, 4), (6, 5), (8, 10)]  # printing original list print("The original list : " + str(test_list))  # Sort tuple list on basis of difference of elements# using sorted() + lambdares = sorted(test_list, key = lambda sub: abs(sub - sub))  # printing resultprint("List after sorting by difference : " + str(res))
Output :
The original list : [(1, 4), (6, 5), (8, 10)]
List after sorting by difference : [(6, 5), (8, 10), (1, 4)]

Method #2 : Using sort() + comparator + cmp()
This is yet another way to perform this task. In this, we pass the sort(), a comparator function which performs the similar difference logic using cmp(). Works only in Python2.

 # Python code to demonstrate working of# Sort tuple list on basis of difference of elements# using sort() + comparator + cmp()  # comparator functiondef diff_sort(ele1, ele2):     return cmp(ele2 - ele2, ele1 - ele1)  # initialize list test_list = [(1, 4), (6, 5), (8, 10)]  # printing original list print("The original list : " + str(test_list))  # Sort tuple list on basis of difference of elements# using sort() + comparator + cmp()test_list.sort(diff_sort)  # printing resultprint("List after sorting by difference : " + str(test_list))
Output :
The original list : [(1, 4), (6, 5), (8, 10)]
List after sorting by difference : [(6, 5), (8, 10), (1, 4)]

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