AttributeError的： '電視' 對象有沒有屬性 '量'

Question

所以這裏是我的代碼

# Television Remote 

class Television(object): 

    def ___init___(self, channel = 15, volume = 20): 
     self.channel = channel 
     self.volume = volume 

    def channell(self, value): 
     if value > 20: 
      print("Max channel is 20") 
      self.channel = 20 
      return self.channel 

     else: 
      self.channel = value 
      return self.channel 
      print("Channel is now ", self.channel) 



    def volume_increase(self): 
     if self.volume != 100: 
      self.volume += 1 
      return self.volume 
     else: 
      return self.volume 



    def volume_decrease(self): 
     if self.volume != 0: 
      self.volume -= 1 
      return self.volume 

     else: 
      return self.volume 


    def channel_up(self): 
     if self.channel == 20: # 20 is the maximum channel allowed 
      self.channel = 1 # so it returns to 1 
      return self.channel 


     else: 
      self.channel += 1 
      return self.channel 


    def channel_down(self): 
     if self.channel == 1: 
      self.channel = 20 
      return self.channel 


     else: 
      self.channel -= 1 
      return self.channel 




c = Television() 
choice = None 
while choice != "0": 
    print(
     """ 
     Television Remote 

     0 - Quit 
     1 - Input Channel 
     2 - Change Channel Up 
     3 - Change Channel Down 
     4 - Volume Up 
     5 - Volume Down 
     """) 

    choice = input("Choice: ") 
    if choice == "0": 
     print("Good Bye") 
    elif choice == "1": 
     value = int(input("What channel? ")) 
     c.channell(value) 
     print("Turning to Channel ", c.channel) 
    elif choice == "2": 
     print("Channel ", c.channel_up()) 
    elif choice == "3": 
     print("Channel ", c.channel_down()) 
    elif choice == "4": 
     print(c.volume_increase()) 
    elif choice == "5": 
     print(c.volume_decrease()) 
    else: 
     print("Choice ", choice, " isn't a valid choice.") 



input("Press enter to exit.") 

當我選擇2 - 4，這將輸出：

(AttributeError: 'Television' object has no attribute 'volume',)

我不明白爲什麼但如果我只寫這個代碼

class Television(object): 
    def __init__(self, channel = 15, volume = 20): 
     self.channel = channel 
     self.volume = volume 

    def volume_increase(self): 
     if self.volume != 100:    
      self.volume += 1 
      return self.volume 
     else: 
      return self.volume 

c = Television() 
choice = None 
while choice != "0": 
    print(
     """ 
     Television Remote 

     0 - Quit 
     1 - Input Channel 
     2 - Change Channel Up 
     3 - Change Channel Down 
     4 - Volume Up 
     5 - Volume Down 
     """) 

    choice = input("Choice: ") 
    if choice == "0": 
     print("Good Bye") 
    elif choice == "1": 
     value = int(input("What channel? ")) 
     c.channell(value) 
     print("Turning to Channel ", c.channel) 
    elif choice == "2": 
     print("Channel ", c.channel_up()) 
    elif choice == "3": 
     print("Channel ", c.channel_down()) 
    elif choice == "4": 
     print(c.volume_increase()) 
    elif choice == "5": 
     print(c.volume_decrease()) 
    else: 
     print("Choice ", choice, " isn't a valid choice.") 

並且只能選擇「4」，代碼工作。有人可以向我解釋爲什麼第一個代碼不起作用，第二個代碼起作用嗎？

如果你不明白我的問題，我會以更詳細的方式向你解釋。

Answer 1

您已經在兩側定義了___init___()函數，並帶有一個額外的下劃線，因此它不是__init__()（初始化方法，而只是另一種實例方法）。

# Television Remote 

class Television(object): 

    def __init__(self, channel = 15, volume = 20): 
     self.channel = channel 
     self.volume = volume