Using Classes in Python to edit a list

Question

So I am trying to define a class and create methods to add, remove, edit, and display from a list. This is what I have so far and I am running into the 'list' object not callable error. I am using some instruction from my class for a lot of the code from a similar project so I am not exactly sure on the pieces that return the added and edited orders. Here is what I have so far:

class Order:
    
    amount = 0.0
    orderType = ""
    number = 0
    
    def __init__(self, amount, orderType, number):
        self.amount = amount
        self.orderType = orderType
        self.number = number

    def setamount(self, amount):
        self.amount = amount

    def setordertype(self, orderType):
        self.orderType = orderType

    def setnumber(self, number):
        self.number = number
    
    def getamount(self):
        return self.amount

    def getordertype(self):
        return self.orderType

    def getnumber(self):
        return self.number
    
    def displayOrder(self):
        print("******************")
        print("*** Order List ***")
        print("Order Number: ", self.number)
        print("Order Type: ", self.orderType)
        print("Order Amount: ", self.amount)
        print("******************")
    
    def displayMenu():
        print("============Welcome to Pizza Palace - Class Demo============")
        print("1. Display Orders.")
        print("2. Add New Order.")
        print("3. Remove Order.")
        print("4. Edit Order.")
        print("5. Save Order.")
        print("9. Exit Program.")
        print("")
        return int(input("Selection: "))
    
    orders = []
    
    def addOrder(orders):
        number = int(input("Enter your order number: "))
        orderType = input("Enter your order type: ")
        amount = float(input("Enter your order amount: "))
        orders[number] = orders(number, orderType, amount)
        return orders
    
    def removeOrder(orders):
        removeNumber = int(input("Which order would you like to remove? "))
        if removeNumber in orders:
            del orders[removeNumber]
        else:
            print("Order not found")
        return orders

    def editOrder(orders):
        badOrder = int(input("Which order would you like to edit?"))
        if badOrder in orders:
            newNumber = int(input("Enter new order number: "))
            newType = input("Enter new order type: ")
            newAmount = float(input("Enter new order amount: "))
            orders[badOrder] = orders(newNumber, newType, newAmount)
        else:
            print("Order not found")
        return orders
    
    def printOrder(orders):
        if len(orders) == 0:
            print("No orders")
        else:
            for x in orders.keys():
                orders[x].displayData()
    
    selection = displayMenu()
    
    if selection != 9:
        if selection == 1:
            printOrder(orders)
        elif selection == 2:
            addOrder(orders)
        elif selection == 3:
            removeOrder(orders)
        elif selection == 4:
            editOrder(orders)
        elif selection == 5:
            saveOrder(orders)
        else:
            print("Invalid input")
    else:
        print("Exiting Program...")

Answer 1

Your problem is in addOrder (with an equivalent mistake in editOrder):

orders[number] = orders(number, orderType, amount)

which is wrong in three separate ways:

1. You're trying to make a new Order, but you uses orders (a list) to do it, not Order (the class). You wanted orders[number] = Order(number, orderType, amount), with a similar change to editOrder
2. You've got the argument order wrong; Order expects amount, orderType, number, but you pass number, orderType, amount, so flip those arguments (or pass them by keyword to remove ambiguity).
3. Even that won't work, because orders is an empty list, and unlike JavaScript (which, if you're not completely new to programming, I'm guessing is the language you're most familiar with, and has unusual Array semantics that allow what you're trying to do), you're not allowed to arbitrarily insert to list indices that don't already have values in Python. For the use case you've got, the best data structure is likely a dict, which allows autovivification of arbitrary keys, so you'd want to change orders = [] to orders = {}.

As it happens, your printOrder is already written to assume orders is a dict, so few, if any, other changes are needed. Bonus: Your membership tests in removeOrder and editOrder, which would never have passed, because the integer isn't in the list, become correct (and much more efficient relative to the equivalent code needed to find an Order in your list) for free.

You have one additional error unrelated to your current problem line, namely, that you use an if, not a while, to receive input from the user, which means you'll never do more than one single operation before the program exits.

I'd suggest replacing:

selection = displayMenu()

if selection != 9:

with:

while (selection := displayMenu()) != 9:

which means you'll run until the user enters 9, not just once at most, and uses the walrus operator to both assign and test a value in the while conditional, replacing the much more verbose idiom in older Python required to write such a loop without doubling the code that assigns to selection in two places (just above the loop and at the end of the loop where it can be accidentally skipped if you ever use continue):

while True:
    selection = displayMenu()
    if selection == 9:
        break