day1_practice.py

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

def find_second_largest(numbers):
    if len(set(numbers))<2:
        return "Error!List must contain at least two unique numbers."

    largest=second_largest=None

    for num in numbers:
        if largest is None or num>largest:
            second_largest=largest
            largest=num
        elif second_largest is None or (num>second_largest and num !=largest):
            second_largest=num

    return second_largest
number_list=[10,20,40,50]
print("Second largest number:",find_second_largest(number_list))
# **********************************************************************88
# def find_second_largest(numbers):
#   """
#   Finds the second largest number in a list.
#
#   Args:
#     numbers: A list of numbers.
#
#   Returns:
#     The second largest number, or None if the list has fewer than 2 elements.
#   """
#   if len(numbers) < 2:
#     return None
#
#   unique_numbers = sorted(list(set(numbers)), reverse=True) #remove duplicates and sort
#   if len(unique_numbers) < 2:
#       return unique_numbers[0] #if only one unique number exists.
#   else:
#       return unique_numbers[1]
#
# # Example usage:
# my_list = [10, 5, 20, 15, 20, 3]
# second_largest = find_second_largest(my_list)
# print(f"The second largest number is: {second_largest}") #output : 15
#
# my_list2 = [10,10,10]
# second_largest2 = find_second_largest(my_list2)
# print(f"The second largest number is: {second_largest2}") #output : 10
#
# my_list3 = [10]
# second_largest3 = find_second_largest(my_list3)
# print(f"The second largest number is: {second_largest3}") #output : None
#
# my_list4 = [10,12]
# second_largest4 = find_second_largest(my_list4)
# print(f"The second largest number is: {second_largest4}") #output : 10
# **********************************************************************
#Write a Python program to remove duplicates from a list while maintaining the original order.

def remove_duplicates(elements):
    seen=set()
    unique_list=[]

    for elem in elements:
        if elem not in seen:
            unique_list.append(elem)
            seen.add(elem)
    return unique_list

elements_list=["orange","Apple","orange","Banana","Apple"]
print(remove_duplicates(elements_list))