w3resource

Python: Find the second largest number in a list

Python List: Exercise - 28 with Solution

Write a Python program to find the second largest number in a list.

Example - 1 :

Python: Find the second largest number in a list

Example - 2 :

Python: Find the second largest number in a list

Example - 3 :

Python: Find the second largest number in a list

Example - 4 :

Python: Find the second largest number in a list

Sample Solution:

Python Code:

# Define a function named 'second_largest' that takes a list of numbers 'numbers' as a parameter
def second_largest(numbers):
    # Check if the length of the 'numbers' list is less than 2; return None in this case
    if len(numbers) < 2:
        return

    # Check if there are only two elements in the 'numbers' list, and they are the same; return None in this case
    if len(numbers) == 2 and numbers[0] == numbers[1]:
        return

    # Create an empty set 'dup_items' to store duplicate items and an empty list 'uniq_items' to store unique items
    dup_items = set()
    uniq_items = []

    # Iterate through the elements in the 'numbers' list
    for x in numbers:
        # Check if 'x' is not in 'dup_items'; if not, add it to 'uniq_items' and 'dup_items'
        if x not in dup_items:
            uniq_items.append(x)
            dup_items.add(x)

    # Sort the 'uniq_items' list in ascending order
    uniq_items.sort()

    # Return the second largest item from the sorted 'uniq_items' list, which is at index -2 (second from the end)
    return uniq_items[-2]

# Call the 'second_largest' function with different lists and print the results
print(second_largest([1, 2, 3, 4, 4]))
print(second_largest([1, 1, 1, 0, 0, 0, 2, -2, -2]))
print(second_largest([2, 2]))  # Edge case with two identical elements, returns None
print(second_largest([1]))  # Edge case with a single element, returns None

Sample Output:

3
1
None
None

Flowchart:

Flowchart: Find the second largest number in a list

Python Code Editor:

Previous: Write a Python program to find the second smallest number in a list.
Next: Write a Python program to get unique values from a list.

What is the difficulty level of this exercise?

Test your Programming skills with w3resource's quiz.



Become a Patron!

Follow us on Facebook and Twitter for latest update.

It will be nice if you may share this link in any developer community or anywhere else, from where other developers may find this content. Thanks.

https://198.211.115.131/python-exercises/list/python-data-type-list-exercise-28.php