“NoneType”对象没有属性“flip”

Question

我目前正在做一个记忆游戏/翻转瓷砖项目。我必须编码4个不同的类，卡片，甲板，游戏和主要。下面是卡片、甲板和游戏类的代码。在编写主类代码之前，我必须先测试所有这些类。当我测试它时，它说：

"'NoneType‘对象没有’flip‘属性“

我不知道错误是从哪里来的。下面的最后3行是我测试类Game()的方法。

class Card():

     #Constructor that initializes the card value and face
    def __init__(self, value):
      self.card_value = value
      self.card_face = False

    #Getter method for Card Value
    def get_value(self): 
      return self.card_value

    #Getter method for Card Face
    def flip(self):
     return self.card_face

    #Setter method to set Card Face
    def set_face(self):
      self.card_face = True

class Deck():
    #Constructor that initializes the number of pairs and total number of cards in the deck
    def __init__(self, pairs):
        self.no_of_pairs = pairs
        self.tot_cards = []
        for cards in range(self.no_of_pairs):
            p1 = Card(cards)
            self.tot_cards.append(p1)
            p2 = Card(cards)
            self.tot_cards.append(p2)

    #Method to deal a card
    def deal(self):
        if self.deck_len() == 0:
           return None
        else:
           return self.tot_cards.pop(0)

    #Method to shuffle the cards in random
    def shuffle_cards(self):
        random.shuffle(self.tot_cards)

    #Method to Return the number of cards in the deck
    def deck_len(self):
        return len(self.tot_cards)

class Game():

    #Constructor that initializes the deck of cards and the rows and columns in the game board and populate the board
    def __init__(self, rows, columns):
        self.deck = Deck((rows * columns)//2)
        self.rows = rows
        self.columns = columns
        self.board = []
        for row in range(self.rows):
            self.board.append([0] * self.columns)
        self.populateBoard()
        self.displayBoard()

    #Method to create the initial 2D list of identical pairs of cards with all facing down
    def populateBoard(self):
        self.deck.shuffle_cards() #shuffle the cards
        for column in range(self.columns):
            for row in range(self.rows):
                self.board[row][column]= self.deck.deal() #place the cards facing down

    #Method to display the cards in the board game
    def displayBoard(self):
        for row in range(self.rows):
            for column in range(self.columns):
                #If not opened face the card down
                if self.board[row][column].flip() == False:
                    print('X ', end="")
                #If the card is open face the card up
                else:
                    print(str(self.board[row][column].get_value()) + " ", end="")
            print("")  # Print newline after each row


test = Game(8,8)
test.populateBoard()
test.displayBoard()

Answer 1

您的错误发生在游戏类的displayBoard函数中，条件为if。该语句为：if self.board[row][column].flip() == False:

发生错误的原因是self.board仅填充了None。

IDLE和PyCharm都会以鲜红色的文本方便地显示错误发生的位置。这称为回溯。这是您的回溯：

Traceback (most recent call last):
   File "C:\Users\delta\AppData\Roaming\JetBrains\PyCharmCE2021.2\scratches\scratch_4.py", line 86, in <module>
        test.displayBoard()
    File "C:\Users\delta\AppData\Roaming\JetBrains\PyCharmCE2021.2\scratches\scratch_4.py", line 76, in displayBoard
        if self.board[row][column].flip() == False:
AttributeError: 'NoneType' object has no attribute 'flip'