Python: Object()没有参数错误，即使整个类模块缩进正确

Question

我已经创建了Book类，即使我正确地编写和缩进了Book方法(实际上我100%地复制了教科书中的代码)，我仍然无法创建类实例。下面是我的类：

class Book:
    """ Information about a book, including title, list of authors,
    publisher, ISBN, and price.
    """

    def __init__(self, title, authors, publisher, isbn, price):
        """ (Book, str, list of str, str, str, number) -> Nonetype

        Create a book, with a title, authors, publisher, isbn number, and price.

        >>> python_book = Book( \
                "Practical Programming", \
                ["Campbell", "Gries", "Montojo"], \
                "Pragmatic Bookshelf", \
                '000-1111', \
                25.0)
        >>> python_book.title
        "Practical Programming"
        >>> python_book.authors
        ["Campbell", "Gries", "Montojo"]
        >>> python_book.publisher
        "Pragmatic Bookshelf"
        >>> python_book.ISBN
        '000-1111'
        >>> python_book.price
        25.0
        """

        self.title = title
        self.authors = authors[:]
        self.publisher = publisher
        self.ISBN = isbn
        self.price = price

    def num_authors(self):
    """ (Book) -> int
        Return the number of authors for the book.
        """
    return len(self.authors)

    def __str__(self):
        """ (Book) -> str

        Return a human-readable string representation of this Book.

        """

        return "Title: {0}, Authors: {1}, Publisher: {2}, ISBN: {3}, Price: {4}".format(self.title, self.authors, self.publisher, self.ISBN, self.price)


    def __eq__(self, other):
        """ (Book, Book) -> bool

        Return True iff this book and other have the same ISBN.
        """

        return self.ISBN == other.ISBN

下面是我在shell中的代码：

>>> import book
>>> python_book = book.Book("Practical Programming", ["Campbell", "Gries", "Montojo"], "Pragmatic Bookshelf", '00-111', 25)

即使这样，我还是得到了"object()不带参数“的错误。我不知道我做错了什么；就像我说的，我从课本上抄袭了所有这些代码，但仍然得到了一个错误。任何帮助都将不胜感激。

Answer 1

你面临的问题到底是什么？我运行了这个程序，它执行得很完美。

class Book:
""" Information about a book, including title, list of authors,
publisher, ISBN, and price.
"""

def __init__(self, title, authors, publisher, isbn, price):
    """ (Book, str, list of str, str, str, number) -> Nonetype

    Create a book, with a title, authors, publisher, isbn number, and price.

    >>> python_book = Book( \
            "Practical Programming", \
            ["Campbell", "Gries", "Montojo"], \
            "Pragmatic Bookshelf", \
            '000-1111', \
            25.0)
    >>> python_book.title
    "Practical Programming"
    >>> python_book.authors
    ["Campbell", "Gries", "Montojo"]
    >>> python_book.publisher
    "Pragmatic Bookshelf"
    >>> python_book.ISBN
    '000-1111'
    >>> python_book.price
    25.0
    """

    self.title = title
    self.authors = authors[:]
    self.publisher = publisher
    self.ISBN = isbn
    self.price = price

def num_authors(self):
    """ (Book) -> int
    Return the number of authors for the book.
    """
    return len(self.authors)

def __str__(self):
    """ (Book) -> str

    Return a human-readable string representation of this Book.

    """

    return "Title: {0}, Authors: {1}, Publisher: {2}, ISBN: {3}, Price: {4}".format(self.title, self.authors, self.publisher, self.ISBN, self.price)


def __eq__(self, other):
    """ (Book, Book) -> bool

    Return True iff this book and other have the same ISBN.
    """

    return self.ISBN == other.ISBN


python_book = Book("Practical Programming", ["Campbell", "Gries", "Montojo"], "Pragmatic Bookshelf", '00-111', 25)
print (python_book)

输出：

Title: Practical Programming, Authors: ['Campbell', 'Gries', 'Montojo'], Publisher: Pragmatic Bookshelf, ISBN: 00-111, Price: 25

Answer 2

在只声明了def init()函数之后，我运行了您的代码，它工作得很好。如其他答案中所述，请检查以下各项：

num_authors()

1. 您要导入的'book‘的缩进位于同一目录中。