将新对象附加到单独变量中的列表中

Question

我对如何将新对象附加到列表中有些困惑。我觉得我正在考虑它，但是让我知道我在这里是否在正确的轨道上。

编辑：删除旧代码

要清楚，我不想直接编辑Display（）中引用的文本文件（然后读出），我想使用附录方法添加一个列表结尾的新书。我使用半隆通过拆分来获得对象，因此，当我添加新书时，他们是否还会有分号呈现以匹配列表的其余部分？

编辑：这是我现在拥有的。

class Book: 

    def __init__(self, title, author, isbn, callnumber, stock, loaned):
        self.title = title
        self.author = author
        self.isbn = isbn
        self.callnumber = callnumber
        self.stock = stock
        self.loaned = loaned
        self.available = int(self.stock)-int(self.loaned)

    def getTitle(self):
        return self.title

    def getAuthor(self):
        return self.author

    def getISBN(self):
        return self.isbn

    def getCallNumber(self):
        return self.callnumber

    def getStock(self):
        return self.stock

    def getLoaned(self):
        return self.loaned

    def getAvailable(self):
        return self.available

    def __repr__(self):
        return self.title + '\t' + self.author + '\t' + self.isbn + '\t' + self.callnumber + '\t' + self.stock + '\t' + self.loaned + '\n'

    def inventory():
        fmtstring = '''{:<50}\t{:<20}\t{:<13}\t{:<13}\t{:<10}\t{:<10}\t{:<10}'''
        print(fmtstring.format("Name","Author","ISBN","Call Number","Stock","Loaned","Available"))
        books = []
        with open("books.txt", "r") as inventoryfile:
            for line in inventoryfile:
                strip_lines=line.strip()
                inventory = strip_lines.split(";")
                book = (Book(inventory[0],inventory[1],inventory[2],inventory[3],inventory[4],inventory[5]))
                books.append(book)
                print(fmtstring.format(*fields(book)))

    @staticmethod
    def input_book():
        title = input("Provide the title of the book> ")
        author = input("Provide the author of the book> ")
        isbn = input("Provide the ISBN of the book> ")
        callnumber = input("Provide the call number of the book> ")
        stock = input("Provide the stock of the book> ")
        return Book(title, author, isbn, callnumber, stock, 0)


And these are called on with menu options.

    while True:
        print()
        print("Westlands Book Inventory Management Subsystem")
        print("1. Display Inventory")
        print("2. Add a Book")
        print("3. Remove a Book")
        print("4. Export Inventory")
        print("5. Quit IMS")
        choice=eval(input("Select an option from the menu> "))
        if(choice==1):
            print()
            print("Displaying Westlands Books Inventory")
            print()
            Book.inventory()
        
        elif(choice==2):
            print()
            print("Adding a Book")
            print()
            Book.input_book()
            print()
            print('Book added successfully.')

这是我的代码的“安全”版本，不会破坏任何内容。我在各个地方尝试了附录命令，但似乎没有起作用。我似乎根本无法将输入返回到Input_books中。谢谢

Answer 1

您从用户输入中创建book的函数应该只是返回 book而不是尝试将其添加到列表中（主要是因为：什么列表？）。如果这是book上的方法，则应该是静态方法（或类方法），而不是实例方法，因为它的目的是 create 一个实例。例如：

@staticmethod
def input_book():
    title = input("Provide the title of the book> ")
    author = input("Provide the author of the book> ")
    isbn = input("Provide the ISBN of the book> ")
    callnumber = input("Provide the call number of the book> ")
    stock = input("Provide the stock of the book> ")
    return Book(title, author, isbn, callnumber, stock, 0)

现在外部您的book类，您可以做：

books = []
while True:
    print()
    print("Westlands Book Inventory Management Subsystem")
    print("1. Display Inventory")
    print("2. Add a Book")
    choice = input("Select an option from the menu> ")
    if choice == "1":
        print(books)
    if choice == "2":
        print()
        print("Adding a Book")
        print()
        books.append(Book.input_book())
        print()
        print('Book added successfully.')

请注意，books不是book，这是的 book s 的 列表。