Python-何时创建类以及何时创建函数 [英] Python - When to create a Class and when to create a Function

问题描述

对，所以我试图使用Python OOP创建一个Contacts应用程序.我对OOP还是很陌生，但仍在尝试了解这些概念.

Right, so I'm trying to create a Contacts application using Python OOP. I'm fairly new to OOP and still trying to get my head around the concepts.

我知道类是所有对象的蓝图.我喜欢将类视为一个实体，每个对象都是该实体的记录.我来自数据库背景，所以这就是为什么我这样解释它，随时可以纠正我.

I understand that a Class is a blueprint for all objects. I like to think of a Class as an entity and each Object is a record of that entity. I am from a Database background so that's why I interpret it like this, feel free to correct me.

无论如何，我正在制作的联系人"应用程序中创建了如下所示的"联系人"类:

Anyways, in the Contacts app I'm making I've created the Class Contacts as outlined below:

 class Contacts():
    def __init__(self, firstName, lastName, address, groupType,
                 telephone, mobile, email, photoField):
        self.firstName = firstName
        self.lastName = lastName
        self.address = address
        self.groupType = groupType
        self.telephone = telephone
        self.mobile = mobile
        self.email = email
        self.photoField = photoField

    def showDetails(self):
        print("First Name:\t", self.firstName)
        print("Last Name:\t", self.lastName)
        print("Address:\t", self.address)
        print("Telephone:\t", self.telephone)
        print("Mobile:\t", self.mobile)
        print("Email:\t", self.email)

现在，如果我想通过Contacts类将联系人添加到我用来存储每个联系人对象的列表中，我是否必须创建一个 AddContacts 类，还是改为创建一个函数?我不知道我对问题的理解是否足够充分，以至于您无法理解我的意思?

Now, if I want to add contacts through the Contacts class into the list I'm using to store each contact object, do I have to create an AddContacts class, or do I create a function instead? I don't know if I'm putting my question across well enough for you to understand what I mean?

我想我想说的是，添加联系人是一个过程，如果您从数据库的角度来看它，则不会创建名为"tbl_AddContacts"的表，因为您可以通过查询来完成此操作或存储过程，所以在我看来，我将定义添加联系人为函数.但是问我的同事谁进行C#编程时，他说添加联系人应该由Class定义.

What I guess I'm trying to say is that adding contacts is a process and if you look at it from a database point of view you wouldn't create a table called "tbl_AddContacts" since you would do that via a query or a stored procedure, so in my view I would define adding contacts being a function. But asking my colleague who does C# programming he says that adding contacts should be defined by a Class.

这对我来说是一个令人困惑的概念，尤其是因为我不了解如何将 AddContacts 类与 Contacts 类链接在一起，甚至不知道如何定义首先是 AddContacts 类！.

This is a confusing concept for me, especially since I don't understand how I would link the AddContacts class with the Contacts class, or even how to define an AddContacts class in the first place!.

这是我定义的用于添加联系人的功能:

Here is the function I defined for adding contacts:

def addContacts():
    firstName = input("First Name: ")
    lastName = input("Last Name: ")
    address = input("Address: ")
    telephone = input("Telephone: ")
    mobile = input("Mobile: ")
    email = input("Email: ")
    print("\n")

    contact = Contacts(firstName, lastName, address, None, telephone, mobile, email, None)

    contactsList.append(contact)

    pickle.dump(contactsList, open("save.p", "wb"))

请帮助我，因为我会将其转换为GUI应用程序(单作业).

Please help me out, since I will turning this into a GUI application (uni assignment).

推荐答案

添加联系人是在做某事，而不是做某事，因此将其作为方法/函数而不是类是有意义的.我建议您的功能实际上应该放在两个单独的位置.

Adding a contact is doing something, rather than being something, so it would make sense as a method/function rather than a class. I would suggest that your functionality should actually be in two separate places.

根据用户输入创建新联系人应该是 Contact 的 class方法:

Creating a new contact from user input should be a class method of Contact:

class Contact(object):

    ...

    @classmethod
    def from_input(cls):
        firstName = input("First Name: ")
        lastName = input("Last Name: ")
        address = input("Address: ")
        telephone = input("Telephone: ")
        mobile = input("Mobile: ")
        email = input("Email: ")
        return cls(firstName, lastName, address, None, 
                   telephone, mobile, email, None)

将新联系人添加到联系人列表应该是:

Adding a new contact to the list of contacts should either be:

1. 例如的实例方法 AddressBook 或 ContactList 类(或保存联系人列表的任何类)；或
2. 单独的功能(如果您没有用于容纳 Contact 实例的类).

1. An instance method of the e.g. AddressBook or ContactList class (or whatever you have holding the contact list); or
2. A separate function if you don't have a class to hold the Contact instances.

例如:

class AddressBook(object):

    ...

    def add_contact(self, contact=None):
        if contact is None:
            contact = Contact.from_input()
        self.contacts.append(contact)

现在，您的UI可以创建一个 Contact ，并将其直接传递给 address_book.add_contact().

Now your UI can create a Contact and pass it straight to address_book.add_contact().

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