布尔输入的函数不打印预期结果

Question

Sorry to bother you at this hour, but I am really struggling with a program. I am working on a python project and I have a very specific set of instructions to follow. Use local named constants in the main module for seat costs and section seat limits that will be passed to the modules and functions described under the following points. These are the instructions.

• Although there are three seating sections in the problem, a set of generic functions will be created that are used for any given section based upon the passed parameters. These functions will be called once for each section: A, B, and C. The general logic for these function is described below:

1.)Include input function (getTickets) that takes section letter and seat limit for given section as parameters. The number of tickets for the given section is returned. This function should only return a valid number of tickets; the validation function, ticketsValid, should be called from this function.

2.)Include validation function (ticketsValid) that takes the tickets sold per section and seat limit per section as passed parameters. A Boolean indicating whether the passed tickets sold for the given section is in the valid range is returned. This validation function will be called from within the previously defined getTickets function.

3.)Include income calculation function (calcIncome) that takes tickets sold and seat cost as passed parameters and returns the income generated for the section.

Now my problem is, I cannot understand why my validator is not working properly. I have it inside another function, but when I run the code it just skips the validating all together. This is my code, any help is appreciated. Again thanks for helping so late at night! :)

def Main():

    aPrice=20
    bPrice=15
    cPrice=10
    alimit=100
    blimit=500
    climit=200
    ticketSold=0
    getTickets(alimit)
    calcIncome(ticketSold,aPrice)
    getTickets(blimit)
    calcIncome(ticketSold,bPrice)
    getTickets(alimit)
    calcIncome(ticketSold,cPrice)


def getTickets(limit):

    ticketSold =int(input("How many tickets were sold in section? "))
    ticketsValid(ticketSold,limit)
    return ticketSold

def ticketsValid(ticketSold,limit):

    if (ticketSold>limit | ticketSold<0):
        print ("ERROR: Section A needs to be a number between 0 and 300")

def calcIncome(ticketSold,price):

    totalIncome= (price*ticketSold)
    print ("The total income for the theater section is "+str(totalIncome))

Main()

Answer 1

1. Here: ticketSold>limit | ticketSold<0 ticketSold>limit | ticketSold<0 change | to or and it will work.

2. Your calcIncome gets ticketSold = 0 , not the newly calculated income. This is because the variable with the same name which you use in your function is local, it is not visible outside the function. To fix it use ticketSold = getTickets(alimit) . In general, it is a good idea to make functions return something if they are supposed to do some calculations, instead of using global variables:

    def calcIncome(ticketSold,price): return price*ticketSold totalIncome = calcIncome(ticketSold,cPrice) print totalIncome 

Answer 2

Let's review your requirements piece by piece.

Use local named constants in the main module for seat costs and section seat limits that will be passed to the modules and functions described under the following points.

So there is a main module and it has local named constants. That's easy.

def income():
    SECTION_A = dict('name': 'A', 'seats': 100, 'price': 20)
    SECTION_B = dict('name': 'B', 'seats': 500, 'price': 15)
    SECTION_C = dict('name': 'C', 'seats': 200, 'price': 10)

Each constant is a dictionary with three slots.

Although there are three seating sections in the problem, a set of generic functions will be created that are used for any given section based upon the passed parameters. These functions will be called once for each section: A, B, and C. The general logic for these function is described below:

1.)Include input function ( getTickets ) that takes section letter and seat limit for given section as parameters. The number of tickets for the given section is returned. This function should only return a valid number of tickets; the validation function, ticketsValid , should be called from this function.

The requirement basically dictates that the function must not return if ticketsValid returns false. I suppose that means we need to loop and ask again if not.

    def getTickets(section_letter, seat_limit):
        while True:
            print "Tickets sold for section %s (max %d):" % (section_letter, seat_limit)
            reply = int(input())
            if ticketsValid(reply, seat_limit):
                return reply
            else:
                print "Sorry, try again."

This will fail if the input cannot be coerced into an int but that is probably acceptable for a first assignment.

2.) Include validation function ( ticketsValid ) that takes the tickets sold per section and seat limit per section as passed parameters. A Boolean indicating whether the passed tickets sold for the given section is in the valid range is returned. This validation function will be called from within the previously defined getTickets function.

If I understand this correctly, "the valid range" means that we must not sell more than the seat limit, or a negative number.

    def ticketsValid(number, seat_limit):
        if 0 <= number <= seat_limit:
            return True
        else:
            return False

It doesn't really make sense to put this in a separate function, IMHO, although the calling function might come out simpler by factoring this out.

3.) Include income calculation function ( calcIncome ) that takes tickets sold and seat cost as passed parameters and returns the income generated for the section.

Again, this is so trivial as to be silly to put in a separate function, but if the calculation would change in the future (add VAT! Copy a percentage to the unemployment fund!) it might be good to have it in one place only.

    def calcIncome(tickets_sold, seat_cost):
        return tickets_sold*seat_cost

What remains now for you is to connect these parts together to a meaningful whole. Take care to remember to assign the return value of every function to a variable!

    for section in [SECTION_A, SECTION_B, SECTION_C]:
        tickets_sold = getTickets(section['name'], section['seats'])
        ...