How to sort a Python list in ascending order

This article will guide you sorting a list in ascending order.

Sorting a List in Ascending Order

Let’s explore different methods to sort a list in ascending order in Python. Sorting is a fundamental operation, and Python offers several ways to achieve this.

Method 1: Using the sort() Method (In-Place Sorting)

The sort() method is a built-in list method that sorts the list in place, meaning it modifies the original list directly. This is an efficient way to sort if you don’t need to preserve the original list.

 my_list = [5, 2, 8, 1, 9, 4]
 my_list.sort()
 print("Sorted list:", my_list)
 

 Sorted list: [1, 2, 4, 5, 8, 9]
 

Explanation:

The sort() method is called directly on my_list. After the call, my_list is sorted in ascending order. The print() statement then displays the modified list.

Method 2: Using the sorted() Function (Creating a New Sorted List)

The sorted() function returns a *new* sorted list without modifying the original list. This is useful when you need to keep the original list intact.

 my_list = [5, 2, 8, 1, 9, 4]
 sorted_list = sorted(my_list)
 print("Original list:", my_list)
 print("Sorted list:", sorted_list)
 

 Original list: [5, 2, 8, 1, 9, 4]
 Sorted list: [1, 2, 4, 5, 8, 9]
 

Explanation:

The sorted() function takes my_list as an argument and returns a new sorted list, which is assigned to sorted_list. The original list remains unchanged. The print() statements display both the original and the sorted lists.

Method 3: Sorting with a Custom Key

Both sort() and sorted() can accept a key argument, which allows you to specify a custom function to be used for comparing elements during the sort. This is powerful for sorting based on complex criteria.

 my_list = ["apple", "banana", "kiwi", "orange"]
 sorted_list = sorted(my_list, key=len) # Sort by length of the string
 print("Sorted list by length:", sorted_list)
 

 Sorted list by length: ['kiwi', 'apple', 'banana', 'orange']
 

Explanation:

In this example, the key argument is set to the built-in len function. This tells sorted() to sort the strings in my_list based on their length, resulting in a list sorted from shortest to longest string.

Method 4: Sorting a List of Tuples

Sorting lists of tuples is common, especially when dealing with data that has multiple attributes. You can use a lambda function to specify which element of the tuple to sort by.

 my_list = [(1, 'z'), (2, 'a'), (3, 'b')]
 sorted_list = sorted(my_list, key=lambda x: x[1]) # Sort by the second element of the tuple
 print("Sorted list of tuples:", sorted_list)
 

 Sorted list of tuples: [(2, 'a'), (3, 'b'), (1, 'z')]
 

Explanation:

Here, a lambda function lambda x: x[1] is used as the key. This function takes a tuple x as input and returns its second element (index 1). The sorted() function uses this to sort the list of tuples based on the alphabetical order of the second element in each tuple.