UnboundLocalError：分配前已引用局部变量“ totalp”

Question

我有一个错误，其中totalp似乎没有进行计算。 用户应该输入他们想要的商品的编号，直到按5停止订单为止，然后计算输入的总价，但是我不知道该怎么做，因为错误是问题的一部分。

这是我得到的错误：

UnboundLocalError: local variable 'totalp之前引用了UnboundLocalError: local variable 'totalp

这是我的代码：

print ("""
MENU ITEMS \t \t  PRICES
1. Pizza \t \t  $7.29 sm  $12.39 lg

TOPPINGS
2. Green Peppers \t  $1.50
3. Mushrooms \t \t  $1.00
4. Pepperoni \t \t  $2.00
5. Complete my order
    """)

name = input("What is your name? ")

p_number = "How many pizzas would you like to purchase? "
t_number = "How many different toppings would you like to add? "

totalp = 0
totalt = 0

def choose_menu():

    print("")
    menu = int(input("What would you like to order? ")) 
    if menu == 0:
        choose_top()
    if menu == 1: 
        p_size = input("What size of pizza would you like? \n (s for small, l for large): ")
        if p_size == "s":
            sprice = 7.29
            totalp += sprice
            print("")
            print("You purchased a small pizza.")
        elif p_size == "l":
            lprice = 12.39
            totalp += lprice
            print("")
            print("You purchased a large pizza.")
        else:
            print("")
            print("Invalid entry, please reenter.")
            choose_menu()
        choose_top()
        choose_menu()
        display_receipt()
    elif menu == 5:
        print("Nothing was purchased.")
    else:
        print("Invalid entry, please reenter.")
        choose_menu()


def choose_top():

    print("")
    topping_choice = int(input("What toppings would you like to add? "))

    if topping_choice == 0:
        top = "No toppings were added."
        display_receipt()
    elif topping_choice == 2:
        top = "Green peppers added."
        price2 = 1.50
        totalt += price2
        choose_top()
    elif topping_choice == 3:
        top = "Mushrooms added."
        price3 = 1.00
        totalt += price3
        choose_top()
    elif topping_choice == 4:
        top = "Pepperonis added."
        price4 = 2.00
        totalt += price4
        choose_top()
    elif topping_choice == 5:
        print("Order has been confirmed.")
        display_receipt()
    else:
        print("Invalid entry, please reenter.")
        choose_top()
    print(top)

if menu == 1:
    p_total = p_number * totalp
    t_total = t_number * totalt
    b_tax_total = p_total + t_total
    tax = int(.0825)
    sales_tax = b_tax_total * tax    
    total_price = b_tax_total + sales_tax
    def display_receipt():

print("")
print("CUSTOMER RECEIPT:")
print("Customer name:", name)
print("The total number of pizzas ordered:", p_number)
print("The total number of toppings ordered:", t_number)
print("Total price before tax:")
print(format(b_tax_total, '.2f'))
print("Sales tax:")
print(format(sales_tax, '.2f'))
print("The total amount due:")
print(format(total_price, '.2f'))   


choose_menu()

Answer 1

我认为您在复制代码缩进时弄糟了。 例如，display_receipt（）似乎现在没有主体。 请解决。 另外，“ if menu == 1”行似乎也不合适。

假设您的缩进效果很好。 上面显示的错误是由于以下事实导致的：totalp已在引用它的函数范围之外分配。 因此，请使用（并且，如果需要，请阅读）“ global”关键字。 基本上，如果您将choose_menu（）函数修改为类似，

def choose_menu():
    global totalp
    print("")
    # code continues as shown above

您将获得想要的行为。 总计可能需要做同样的事情。

值得一提的是，对于琐碎的情况使用全局变量通常不是最好的方法。 如果可以，请尝试传递该值，或者在这种情况下使用允许引用的类型（例如列表）。