Python 2.7假期费用计算程序报错求助：NameError问题排查

Hey there! Let's figure out why you're hitting that NameError and get your holiday cost calculator working properly.

What's Causing the NameError? #

The issue is super straightforward: when you call hotel_cost(), plane_cost(), and car_rental() in your code, you're running the functions but not saving their return values to the nights, city, and days variables that holiday_cost() expects. Python has no idea what those variable names refer to when you try to pass them later, hence the error.

Fixing the Code (Plus a Few Extra Improvements) #

Here's a corrected version of your code with explanations of the changes:

def hotel_cost(nights):
    return nights * 875

def plane_cost(city):
    ticket = 0
    # Removed the unnecessary while loop that was causing unexpected behavior
    if city == '1':
        ticket = 750
    elif city == '2':
        ticket = 850
    elif city == '3':
        ticket = 600
    else:
        print 'You have selected an invalid option'
        ticket = 0  # Ensure we always return a number, not None
    return ticket

def car_rental(days):
    return days * 275

def holiday_cost(nights, city, days):
    # Used clearer variable names instead of overwriting the input parameters
    hotel_total = hotel_cost(nights)
    plane_total = plane_cost(city)
    car_total = car_rental(days)
    return hotel_total + plane_total + car_total

# KEY FIX: Assign the function results to the variables we'll use later
nights = int(raw_input('How many nights will you be staying? '))
city = raw_input('\n1. O.R. Tambo International\n2. Capetown International\n3. King Shaka International\nWhere you flying to? ')
days = int(raw_input('How many days will you need a car for?: '))

total = holiday_cost(nights, city, days)
print "Total holiday cost: R{}".format(total)

Breakdown of Changes #

1. Fixed the Variable Definition Issue:
   We now assign the output of each function call to the nights, city, and days variables. This gives Python concrete values to pass to holiday_cost().

2. Cleaned Up the plane_cost Function:

   • Removed the redundant while loop that would have caused infinite loops if the user entered an invalid option.
   • Added a ticket = 0 in the else block to ensure the function always returns a numeric value (instead of None), which prevents a TypeError when calculating the total cost.

3. Improved Readability in holiday_cost:
   Instead of overwriting the input parameters (nights = hotel_cost(nights)), we use separate variables like hotel_total to make the code easier to follow.

Now when you run the code, it should correctly calculate and display your total holiday cost without any errors!

内容的提问来源于stack exchange，提问作者Zee Dhlomo