python - 全局名称未定义错误

Question

我的折扣变量总是出错。名称错误:未定义全局名称“折扣”。请看看我的代码并帮助我。我根本不想修改函数的参数。

def finddiscount(quantity):
    if quantity >= 1 and quantity <= 9:
        discount = 0
    elif quantity >= 10 and quantity <= 19:
        discount = .2
    elif quantity >= 20 and quantity <= 49:
        discount = .30
    elif quantity >= 50 and quantity <= 99:
        discount = .40
    elif quantity >= 100:
        discount = .50
    return discount
def calctotal(quantity, price):
    finddiscount(quantity)
    disc = (price*quantity)*discount
    total = (price*quantity)
    due = (price*quantity)-(price*quantity)*dicount
    print ("\t","Order total $",format(total, "10.2"),"\n\t","Discount    $",format(disc,"10.2"),"\n\t","Amount Due $",format (due, "10.2"),sep="")
def main():
    quantity = int(input("How many packages where purchased?"))
    price = float(input("How much is each item?"))
    calctotal(quantity, price)
main()

Answer 1

如果您想在多 block 范围内访问它，您必须将 discount 声明为全局变量。

discount = 0

def finddiscount(quantity):
    ...
    global discount    # Needed to modify global copy of discount
    discount = 1