[Tutor] inheritance problem

Roelof Wobben rwobben at hotmail.com
Fri Oct 1 09:18:38 CEST 2010




----------------------------------------
> From: rwobben at hotmail.com
> To: alan.gauld at btinternet.com; tutor at python.org
> Date: Fri, 1 Oct 2010 06:19:29 +0000
> Subject: Re: [Tutor] inheritance problem
>
>
>
>
> ----------------------------------------
>> To: tutor at python.org
>> From: alan.gauld at btinternet.com
>> Date: Fri, 1 Oct 2010 00:59:06 +0100
>> Subject: Re: [Tutor] inheritance problem
>>
>> "Roelof Wobben" wrote
>>
>>> So i have this programm now :
>>
>>> class Deck:
>>> def __init__(self):
>>> self.cards = []
>>> for suit in range(4):
>>> for rank in range(1, 14):
>>> self.cards.append(Card(suit, rank))
>>>
>>> def deal(self, hands, num_cards=999):
>>> num_hands = len(hands)
>>> for i in range(num_cards):
>>> if self.is_empty(): break # break if out of cards
>>> card = self.pop() # take the top card
>>> hand = hands[i % num_hands] # whose turn is next?
>>> hand.add(card) # add the card to the hand
>>>
>>> def shuffle(self):
>>> import random
>>> num_cards = len(self.cards)
>>> for i in range(num_cards):
>>> j = random.randrange(i, num_cards)
>>> self.cards[i], self.cards[j] = self.cards[j],
>>> self.cards[i]
>>>
>>> def remove(self, card):
>>> if card in self.cards:
>>> self.cards.remove(card)
>>> return True
>>> else:
>>> return False
>>> def is_empty(self):
>>> return (len(self.cards) == 0)
>>
>>> But now Im getting this error message:
>>>
>>> Traceback (most recent call last):
>>> File "C:\Users\wobben\workspace\oefeningen\src\test.py", line 126,
>>> in
>>> game.deck.deal([hand], 13)
>>> File "C:\Users\wobben\workspace\oefeningen\src\test.py", line 24,
>>> in deal
>>> card = self.pop() # take the top card
>>> AttributeError: Deck instance has no attribute 'pop'
>>>
>>>
>>> What went wrong here.
>>
>> The error tells you what is wrong, the Deck has no attribute called
>> pop.
>> Can you see a pop anywhere?
>
> I only see a pop here : card = self.pop() # take the top card
> but no function called pop.
>
>
>> So if the code you copied has an error how should it assign a card?
>
>
> I assigned a card by this code :
>
> def deal(self, hands, num_cards=999):
> num_hands = len(hands)
> for i in range(num_cards):
> if self.is_empty(): break # break if out of cards
> card = self.pop() # take the top card
> hand = hands[i % num_hands] # whose turn is next?
> hand.add(card) # add the card to the hand
>
>
>
>> Where are the cards stored? How would you get the first card from
>> the collection? Does that work?
>
> The cards are stored in a directory named cards.
> The hands are stored in a directory named hands
>
>>
>> Think about what the error is telling you and think about how you
>> would fix it. If you don't understand what the error is saying then
>> tell
>> us and we can explain it, but in this case its pretty clearly stated
>> and is one you have seen before.
>
>
> The error is telling me that the function pop does not exist for a directory,
> So solution is to find out which object contains pop and then change the code.
>
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Hello, 
 
I make a big mistake.
Both card and hands are lists and pop can be used on a list.
So as Joel said in this rule card = self.pop() there is no list named so I think it must be self.hands.pop()
 
Roelof
  		 	   		  


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