Traceback（最近一次通话最后一次）：和 TypeError：

Question

我仍然是 Python 的初学者，目前正在使用 codecademy。我决定将其中一个练习程序稍微复杂化，我遇到了这个错误：

Traceback (most recent call last):
File "python", line 30, in <module>
File "python", line 24, in trip_cost
File "python", line 18, in rental_car_cost
TypeError: unsupported operand type(s) for -: 'unicode' and 'int'

这是我的代码：

def hotel_cost(nights):
  # the hotel costs $140 per night
  return 140 * nights

def plane_ride_cost(city):
  if city == "Charlotte":
    return 183
  elif city == "Tampa":
    return 220
  elif city == "Pittsburgh":
    return 222
  elif city == "Los Angeles":
    return 475

def rental_car_cost(days):
  cost = days * 40
  if days >= 7:
    cost -= 50
  elif days >= 3 and days < 7:
    cost -= 20
  return cost

def trip_cost(city, days, spending_money):
  return rental_car_cost(days) + hotel_cost(days - 1) + plane_ride_cost(city) + spending_money

x = raw_input("Where are you going? ")
y = raw_input("How many days are you going for? ")
z = raw_input("How much spending money are you taking? ")

print trip_cost(x, y, z)

任何帮助将不胜感激，谢谢！我是初学者，所以我的 python 术语有点生疏。

Answer 1

您正在执行days - 1 或cost -= 50 但days 和cost 是用户输入，因此是一个字符串（在您的情况下更准确的unicode 字符串），您应该在执行任何操作之前转换为int（尤其是数学），因为这是你的意图：

y = int(raw_input("How many days are you going for? "))
z = int(raw_input("How much spending money are you taking? "))

这是因为您将它们当作数字来使用而不进行转换

但是请注意，输入除数字以外的任何内容都会产生错误，但这是另一个问题的主题