if语句

print("----")
requested_toppings = ['mushrooms','green peppers','extra cheese']
for requested_topping in requested_toppings:
    print("Adding " + requested_topping +".")
print("\nFinished making your pizza!")

print("----")
requested_toppings = ['mushrooms','green peppers','extra cheese']
for requested_topping in requested_toppings:
    if requested_topping == 'green peppers':
        print("Sorry, We are out of green peppers right now.")
    else:
        print("Adding " + requested_topping + ".")
print("\nFinished making your pizza!")

print("----")
requested_toppings = []
if requested_toppings:
    for requested_topping in requested_toppings:
        print("Adding "+requested_topping+".")
    print("Finished making your pizza!")
else:
    print("Are you sure want to plain pizza?")
    
print("----")        
available_toppings = ['mushrooms','olives','green peppers', 
                        'pepperoni','pineapple','extra cheese']
requested_toppings = ['mushrooms','french fries', 'extra cheese']
for requested_topping in requested_toppings:
    if requested_topping in available_toppings:
        print("Adding " + requested_topping + ".")
    else:
        print("Sorry, We don't have " + requested_topping + ".")
print("\nFinished making your pizza.")

print("====")
users = ['Zhang Yunyi','Liu Jun', 'Li Xia', 'Xu Yuchi', 'Admin']
users.clear()
if users:
    for user in users:
        if user == 'Admin':
            print("Hello admin, would you like to see a status report?")
        else:
            print("Hello " + user + ", thank you for logging in again")
else:
    print("We need to find some users!")

print("====")
current_users = ['Zhang Yunyi','Liu Jun', 'Li Xia', 'Xu Yuchi', 'Admin']
new_users = ['ZHANG Yunyi', "Ao Min", 'Liu Jun', 'Wang Wenbin', 'Pan Chunyun']

for user in new_users:
    used = 0
    for cuser in current_users:
        if user.upper() == cuser.upper():
            print("You need to input other username")
            used = 1
            break;
    if used == 0:
        print(user + " is not been used")
        
print("====")
nums = [1,2,3,4,5,6,7,8,9]
for num in nums:
    if num == 1:
        print(str(num)+"st")
    elif num == 2:
        print(str(num)+"nd")
    elif num == 3:
        print(str(num)+"rd")
    else:
        print(str(num)+"th")