The task is to write a Python Program to sort a list of tuples in increasing order by the last element in each tuple.
Input: [(1, 3), (3, 2), (2, 1)] Output: [(2, 1), (3, 2), (1, 3)] Explanation: sort tuple based on the last digit of each tuple.
Methods #1: Using sorted().
Sorted() method sorts a list and always returns a list with the elements in a sorted manner, without modifying the original sequence.
Approach:
- Take a list of tuples from the user.
- Define a function that returns the last element of each tuple in the list of tuples.
- Define another function with the previous function as the key and sort the list.
- Print the sorted list.
Python3
def last(n): return n[-1] def sort(tuples): return sorted(tuples, key=last) a=[(1, 3), (3, 2), (2, 1)]print("Sorted:")print(sort(a)) |
Output:
Sorted: [(2, 1), (3, 2), (1, 3)]
Methods #2: Using Bubble Sort.
Access the last element of each tuple using the nested loops. This performs the in-place method of sorting. The time complexity is similar to the Bubble Sort i.e. O(n^2).
Python3
# Python program to sort # a list of tuples by the second Item # Function to sort the list # of tuples by its second item def Sort_Tuple(tup): # getting length of list of tuples lst = len(tup) for i in range(0, lst): for j in range(0, lst-i-1): if (tup[j][-1] > tup[j + 1][-1]): temp = tup[j] tup[j]= tup[j + 1] tup[j + 1]= temp return tup # Driver Code tup =[(1, 3), (3, 2), (2, 1)] print(Sort_Tuple(tup)) |
Output:
[(2, 1), (3, 2), (1, 3)]
Methods #3: Using sort().
The sort() method sorts the elements of a given list in a specific ascending or descending order.
Python3
# Python program to sort a list of # tuples by the second Item using sort() # Function to sort hte list by second item of tuple def Sort_Tuple(tup): # reverse = None (Sorts in Ascending order) # key is set to sort using second element of # sublist lambda has been used tup.sort(key = lambda x: x[-1]) return tup # Driver Code tup = [(1, 3), (3, 2), (2, 1)] # printing the sorted list of tuples print(Sort_Tuple(tup)) |
Output:
[(2, 1), (3, 2), (1, 3)]
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