Given a list of tuples, write a Python program to sort the tuples alphabetically by the first item of each tuple. Examples:
Input: [("Amana", 28), ("Zenat", 30), ("Abhishek", 29), ("Nikhil", 21), ("B", "C")]
Output: [('Amana', 28), ('Abhishek', 29), ('B', 'C'), ('Nikhil', 21), ('Zenat', 30)]
Input: [("aaaa", 28), ("aa", 30), ("bab", 29), ("bb", 21), ("csa", "C")]
Output: [('aa', 30), ('aaaa', 28), ('bab', 29), ('bb', 21), ('csa', 'C')]
Method 1: Using Bubble sort Using the technique of Bubble Sort to we can perform the sorting. Note that each tuple is an element in the given list. Access the first 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 alphabetically# Function to sort the list of# tuplesdef SortTuple(tup): # Getting the length of list # of tuples n = len(tup) for i in range(n): for j in range(n-i-1): if tup[j][0] > tup[j + 1][0]: tup[j], tup[j + 1] = tup[j + 1], tup[j] return tup # Driver's codetup = [("Amana", 28), ("Zenat", 30), ("Abhishek", 29), ("Nikhil", 21), ("B", "C")] print(SortTuple(tup)) |
Output:
[('Abhishek', 29), ('Amana', 28), ('B', 'C'), ('Nikhil', 21), ('Zenat', 30)]
Method 2: Using sort() method While sorting via this method the actual content of the tuple is changed, and just like the previous method, the in-place method of the sort is performed.
Python3
# Python program to sort a list of# tuples using sort() # Function to sort the listdef SortTuple(tup): # reverse = None (Sorts in Ascending order) # key is set to sort using first element of # sublist lambda has been used tup.sort(key = lambda x: x[0]) return tup # Driver's codetup = [("Amana", 28), ("Zenat", 30), ("Abhishek", 29), ("Nikhil", 21), ("B", "C")] print(SortTuple(tup)) |
Output:
[('Abhishek', 29), ('Amana', 28), ('B', 'C'), ('Nikhil', 21), ('Zenat', 30)]
Method 3: Using sorted() method sorted() method is a method of list class that returns the sorted list without making any changes to the original list.
Python3
# Python program to sort a list of# tuples using sorted() # Function to sort the listdef Sort_Tuple(tup): # reverse = None (Sorts in Ascending order) # key is set to sort using first element of # sublist lambda has been used return(sorted(tup, key = lambda x: x[0])) # Driver Code tup = [("Amana", 28), ("Zenat", 30), ("Abhishek", 29), ("Nikhil", 21), ("B", "C")] # printing the sorted list of tuplesprint(Sort_Tuple(tup)) |
Output:
[('Abhishek', 29), ('Amana', 28), ('B', 'C'), ('Nikhil', 21), ('Zenat', 30)]
Time Complexity: O(n*logn), as sorted() function is used.
Auxiliary Space: O(n), where n is length of list.
