什么是错这个脚本

Question

def hotel_cost(nights): 
    cost = nights * 40 
    return cost 
def plane_ride_cost(city): 
    if city == "charolette": 
     cost = 180 
    elif city == "los angeles": 
     cost = 480 
    elif city == "tampa": 
     cost = 200 
    elif city == "pittspurgh": 
     cost = 220 
    return cost 
def rental_car_cost(days): 
    cost = days * 40 
    if days >= 7: 
     cost -= 50 
    elif days >= 3: 
     cost -= 20 
    return cost 

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

city_list = ("charolette", "los angeles", "tampa", "pittspurgh") 

print "we only support one of those cities" + str(city_list) 

city = raw_input (" please choose the city you want to go ") 
days = 0 
spending_money = 0 
if city in city_list: 
    days = raw_input("how much days you wanna stay ") 
    spending_money = raw_input("how much money do you wanna spend there") 
    print trip_cost(city, days, spending_money) 
else: 
    print 'error' 

它总是产生这个错误

rint trip_cost(city, days, spending_money) 
    File "/home/tito/test 3 .py", line 23, in trip_cost 
    return (hotel_cost(days)) + (plane_ride_cost(city)) + (rental_car_cost(days)) + (spending_money) 
TypeError: cannot concatenate 'str' and 'int' objects 

Answer 1

用户输入转换为相应的数据类型应该有所帮助：

if city in city_list: 
    days = int(raw_input("how many days you wanna stay ")) 
    spending_money = float(raw_input("how much money do you wanna spend there")) 

你总是得到一个字符串返回从raw_input。你可以将一个字符串转换为一个整数int()或一个浮点数float()。如果字符串不能转换成这种数据类型，你将得到一个ValueError异常。