Find Second Large Number in List Using While Loop in Python

In this code we are going to discuss how to find the second-largest number in a list using a while loop in Python:

Simple code:

my_list = [5, 12, 7, 19, 3, 8, 10]
largest_num = my_list[0]
second_largest = None
i = 1
while i < len(my_list):
    if my_list[i] > largest_num:
        second_largest = largest_num
        largest_num = my_list[i]
    elif my_list[i] > second_largest or second_largest is None:
        second_largest = my_list[i]
    i += 1
print("The second largest number in the list is:", second_largest)

Output:

The second largest number in the list is: 12

Code with comments:

# initialize the list of numbers
my_list = [5, 12, 7, 19, 3, 6, 10]

# initialize the largest_num variable to the first element of the list
largest_num = my_list[0]

# initialize the second_largest variable to None
second_largest = None

# initialize the counter i to 1
i = 1

# continue looping until i reaches the end of the list
while i < len(my_list):
    # check if the current element is greater than the largest_num variable
    if my_list[i] > largest_num:
        # update the second_largest variable to the current largest_num value
        second_largest = largest_num
        # update the largest_num variable to the current element
        largest_num = my_list[i]
    # check if the current element is greater than the second_largest variable or if second_largest is None
    elif my_list[i] > second_largest or second_largest is None:
        # update the second_largest variable to the current element
        second_largest = my_list[i]
    # increment the counter i by 1
    i += 1

# print the second largest number in the list
print("The second largest number in the list is:", second_largest)

In the above code, we first initialize the list of numbers my_list, the largest_num variable to the first element of the list, and the second_largest variable to None.

We also initialize the counter i to 1.

We use a while loop to iterate through the list and update the largest_num and second_largest variables based on the current element.

Finally, we print the second largest number in the list using the print() function.