为什么 python 认为有 6 个位置 arguments 而我只有 5 个？

Question

So I'm trying to use that Domino's pizza api with this program I'm making but I want to use user inputs instead of coded-in customer data. To do so, I coded this:

from pizzapi import Customer
address = input("Street Address: ") + ', ' + input('City: ') + ', ' + input('State Abbreviation: ') + ', ' + input('5-Digit Zip Code: ')
customer = Customer(input('First Name: '), input('Last Name: '), input('Email: '), input('Phone Number: '), str(address))
print(customer)

but when I try to run it, I get this error:

customer = Customer(input('First Name: '), input('Last Name: '), input('Email: '), input('Phone Number: '), str(address))
TypeError: Customer.__init__() takes from 1 to 5 positional arguments but 6 were given

How do I get rid of this error? I'm only inputting 5 parameters?

edit: the customer module looks like this:

class Customer:
    """The Customer who orders a pizza."""

    def __init__(self, fname='', lname='', email='', phone='', address=None):
        self.first_name = fname.strip()
        self.last_name = lname.strip()
        self.email = email.strip()
        self.phone = str(phone).strip()
        self.str_address = address
        self.address = Address(*address.split(','))

    def save(self, filename="customers/customer1.json"):
        """
        saves the current customer to a .json file for loading later
        """
        if not filename.startswith("customers"):
            filename = "customers/" + filename
        json_dict = {"first_name": self.first_name,
             "last_name": self.last_name,
             "email": self.email,
             "phone": self.phone,
             "address": self.str_address}

        with open(filename, "w") as f:
            json.dump(json_dict, f)

    @staticmethod
    def load(filename):
        """
        load and return a new customer object from a json file
        """
        with open(filename, "r") as f:
            data = json.load(f)

            customer = Customer(data["first_name"], 
                                data["last_name"],
                                data["email"],
                                data["phone"],
                                data["address"])
        return customer

    def __repr__(self):
        return "Name: {} {}\nEmail: {}\nPhone: {}\nAddress: {}".format(
            self.first_name,
            self.last_name,
            self.email,
            self.phone,
            self.address,
        )

Answer 1

You might need to force Python to load the latest definition of the module the class is in.

To be clear, Python says there are six arguments because it is counting the implicit self argument.

But the real strange thing is why it's saying it expects 1-5 arguments instead of 1-6. The Customer definition you posted has the right number of parameters in the __init__ method that the error you're reporting wouldn't happen.

This suggests that your Python process is using a different definition of Customer . I can think of a few possibilities:

0. Make sure you save your changes to the pizzapi module file where you define Customer before running the code. (This might not be obvious if you are used to setups where you don't have to save code to try running it, but most IDEs for Python, and the raw python command itself, run the code you have saved, not the code as it is in your editor.)

1. There is a module with the same name in a different location which is being loaded first. (Perhaps an older copy of pizzapi that you saved by making a copy?)

2. There is another import running later in your code which gets another Customer definition from a different module (a from example import * could do it, if the example module has a Customer defined).

3. An older definition of the same module was already cached in the running Python process (such as when you use Jupyter/iPython, run python in a terminal to get a REPL, or have a little live Python panel in your IDE).

You can easily check the first problem: do import pizzapi and then print(pizzapi.__file__) . That will tell you what exact file path the pizzapi module is being loaded from. Check carefully if that's exactly the file that has your latest Customer definition.

The second is similarly easy to check: just run print(Customer.__module__) right before the customer = Customer(...) line. This will show you where the Customer being used in that line is coming from.

Once the first and second are ruled out or fixed, we get to the third one:

When a Python process runs import pizzapi or from pizzapi import Customer , it caches the definition of pizzapi . After that, even if you change the definition of Customer , a second import pizzapi or from pizzapi import Customer will not pick up the changes.

One way to do this is to just quit the Python process and start over.

Another way is to use importlib.reload :

1. First make sure to run import pizzapi before the reload(pizzapi) if you haven't already.

2. Then do from importlib import reload and reload(pizzapi) .

3. Finally, you'll need to re-run imports of specific things from the module such as from pizzapi import Customer .