看看这个作品
注意项目顺序价格

STATE_TAX_RATE = 0.6
CITY_TAX_RATE = 0.2
itemPrice = float(input("Enter price: "))
totalTax = itemPrice * STATE_TAX_RATE + itemPrice * CITY_TAX_RATE

totalPrice = itemPrice + totalTax

print("Item price is " + str(itemPrice) + " and total tax is " + str(totalTax))
print("Total price is " + str(totalTax))

这里没有循环。如下所示重新排序代码将修复您的问题：

STATE_TAX_RATE = 0.6
CITY_TAX_RATE = 0.2

itemPrice = float(input("Enter price: "))

totalTax = itemPrice * STATE_TAX_RATE + itemPrice * CITY_TAX_RATE

totalPrice = itemPrice + totalTax

print("Item price is " + str(itemPrice) + " and total tax is " + str(totalTax))
print("Total price is " + str(totalTax))

Name错误：名称'itemPrice'未定义
这是您得到的错误，因为您在计算之后（在需要的地方）分配了itemPrice，所以您得到了一个NameError
通过重新排序代码，

itemPrice = float(input("Enter price: "))

在计算totalTax之前，您的错误应该被修复
完全正确的代码-

STATE_TAX_RATE = 0.6
CITY_TAX_RATE = 0.2

itemPrice = float(input("Enter price: "))
''' now it is assigned first so it will indeed carry out the calculation 
afterwards without any errors '''

totalTax = itemPrice * STATE_TAX_RATE + itemPrice * CITY_TAX_RATE

totalPrice = itemPrice + totalTax

print("Item price is " + str(itemPrice) + " and total tax is " + 
str(totalTax))
print("Total price is " + str(totalTax))

你试图使用一个未定义的变量。将itemPrice = ...行移高，这样它就在任何itemPrice变量的使用之前。
顺便说一下，这里没有循环.
完整代码：

STATE_TAX_RATE = 0.6
CITY_TAX_RATE = 0.2

itemPrice = float(input("Enter price: "))

totalTax = itemPrice * STATE_TAX_RATE + itemPrice * CITY_TAX_RATE

totalPrice = itemPrice + totalTax

print("Item price is " + str(itemPrice) + " and total tax is " + str(totalTax))
print("Total price is " + str(totalTax))