嘗試將所有節點列印為鏈表中的字串，但它列印的是位置

具有屬性的圖書物件：標題、作者、年份

class Book():
    def __init__(self, title = "", author = "", year = None):
        self.title = title
         self.author = author
    self.year = year

def getTitle(self):
    return self.title

def getAuthor(self):
    return self.author

def getYear(self):
    return self.year

def getBookDetails(self):
    string = ("Title: {}, Author: {}, Year: {}"\
                 .format(self.title, self.author, self.year))
    return string
    

名為 BookCollection 的鏈表

class BookCollection()
    def __init__(self):
        self.head = None
    
    def insertBook(self, book)
       temp = BookCollectionNode(book)
       temp.setNext(self.head)
       self.head = temp

    def getAllBooksInCollection(self):
        node = self.head

這是下面的問題。我使用 while 回圈列印每個節點，但是它列印節點的位置

        while node:
            print(node)
            node = node.next

名為 BookCollectionNode 的節點類

class BookCollectionNode():

    def __init__(self, data):
       self.data = data
       self.next = None

    def getData(self):
       return self.data

    def getNext(self):
        return self.next

    def setData(self, newData):
        self.data = newData
    
    def setNext(self, newNext):
        self.next = newNext

使用下面的函式列印鏈表的節點

b0 = Book("Cujo", "King, Stephen", 1981)
b1 = Book("The Shining", "King, Stephen", 1977)
b2 = Book("Ready Player One", "Cline, Ernest", 2011)
b3 = Book("Rage", "King, Stephen", 1977)

bc = BookCollection()
bc.insertBook(b0)
bc.insertBook(b2)
bc.insertBook(b3)

print(bc.getAllBooksInCollection())

uj5u.com熱心網友回復：

使固定

由于 node 是 a BookCollectionNode，您需要訪問它的book屬性，然后呼叫getBookDetails()方法

def getAllBooksInCollection(self):
    node = self.head
    while node:
        print(node.data.getBookDetails())
        node = node.next

并在bc.getAllBooksInCollection()沒有列印的情況下呼叫。由于沒有 return 陳述句，它回傳None您看到的列印內容

改進

1. 似乎您并不真的需要訪問您的屬性的方法，但是如果您真的想要它們，請使用 @property

   class Book:
       def __init__(self, title="", author="", year=None):
           self._title = title
           self._author = author
           self._year = year
       @property
       def title(self):
           return self._title
       @property
       def author(self):
           return self._author
       @property
       def year(self):
           return self._year
   

2. 覆寫方法__str__以在列印時獲取內置字串

   class BookCollectionNode:
       def __str__(self):
           return str(self.data)
   
   class Book:    
       def __str__(self):
           return f"Title: {self._title}, Author: {self._author}, Year: {self._year}"
   

3. 對于BookCollectionNodegetter/setter，正確的方法是

   class BookCollectionNode:
       def __init__(self, data):
           self._data = data
           self._next = None
       @property
       def data(self):
           return self._data
       @property
       def next(self):
           return self._next
       @data.setter
       def data(self, newData):
           self._data = newData
       @next.setter
       def next(self, newNext):
           self._next = newNext
   

最后BookCollection班級變成

class BookCollection:
    def __init__(self):
        self.head = None
    def insert_book(self, book):
        temp = BookCollectionNode(book)
        temp.next = self.head
        self.head = temp
    # 'print_' and not 'get_' as you don't return anything
    def print_all_books_in_collection(self):
        node = self.head
        while node:
            print(node)
            node = node.next

uj5u.com熱心網友回復：

我認為，您需要在建構式中添加一個 data 引數才能得到如下內容：

class Node:

    def __init__(self, data, next=None):
        self.data = data
        self.next = next

# Using an object of a Book with attributes: Title, Author, Year
b0 = Book("Cujo", "King, Stephen", 1981)
b1 = Book("The Shining", "King, Stephen", 1977)
b2 = Book("Ready Player One", "Cline, Ernest", 2011)
b3 = Book("Rage", "King, Stephen", 1977)

head = Node(b0, Node(b1, Node(b2, Node(b3))))


def print_list(head, end='\n'):
    while head:
        # You can extend the below logic
        print(head.data, end=' -> ' if head.next else '') 
        head = head.next
    print(end=end)


print_list(head)

標籤：Python 细绳 印刷

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