this is my first time at stack overflow so I'm sorry if the format doesn't fit quite right with the site. I just recently started learning programming, almost 2 weeks have passed since. I'm learning python from http://openbookproject.net/thinkcs/python/english3e/index.html and everything had been quite nice until now, where I just got stuck for hours. I googled a lot but couldn't find a proper solution to my problem so here I am.
I'm trying to get the OldMaidGame() run without problems as explained on CH17. http://openbookproject.net/thinkcs/python/english3e/ch17.html - Most of the code also comes from the previous chapter.
What I've found out is I can't get the Deck.remove, Hand.remove_matches, or any other kind of remove function to work. After some debugging I found out that the problem occurs when the program checks if the given card is present in the deck/hand/etc. It can't ever make a match. Then after some looking back on the chapter, (in ch16), I found out that 'if card in deck/hand/etc: remove(card)' etc looks up the .cmp() of the object to determine if the card actually exists in the deck/hand/etc. This is my version of the cmp after doing the additions for 'ace's on the given code from the e-book.
def __cmp__(self, other):
""" Compares cards, returns 1 if greater, -1 if lesser, 0 if equal """
# check the suits
if self.suit > other.suit: return 1
if self.suit < other.suit: return -1
# suits are the same... check ranks
# check for aces first.
if self.rank == 1 and other.rank == 1: return 0
if self.rank == 1 and other.rank != 1: return 1
if self.rank != 1 and other.rank == 1: return -1
# check for non-aces.
if self.rank > other.rank: return 1
if self.rank < other.rank: return -1
# ranks are the same... it's a tie
return 0
The cmp itself seems fine afaik, ofc I could use some tips on how to make it better (like with ace checks). So I have no idea why the card in deck/hand checks always return false. This was the given remove function:
class Deck:
...
def remove(self, card):
if card in self.cards:
self.cards.remove(card)
return True
else:
return False
Desperately trying to get it to work, I came up with this:
class Deck:
...
def remove(self, card):
""" Removes the card from the deck, returns true if successful """
for lol in self.cards:
if lol.__cmp__(card) == 0:
self.cards.remove(lol)
return True
return False
Seemed to work fine, until I moved on to the other non-working remove functions:
class OldMaidHand(Hand):
def remove_matches(self):
count = 0
original_cards = self.cards[:]
for card in original_cards:
match = Card(3 - card.suit, card.rank)
if match in self.cards:
self.cards.remove(card)
self.cards.remove(match)
print("Hand {0}: {1} matches {2}".format(self.name, card, match))
count = count + 1
return count
I again made some adjustments:
class OldMaidHand(Hand):
def remove_matches(self):
count = 0
original_cards = self.cards[:]
for card in original_cards:
match = Card(3 - card.suit, card.rank)
for lol in self.cards:
if lol.__cmp__(match) == 0:
self.cards.remove(card)
self.cards.remove(match)
print("Hand {0}: {1} matches {2}".format(self.name, card, match))
count = count + 1
return count
The removing worked fine for the card, but it would give an error (x not in list) when I tried to remove match. Another our or so, I might've been able to make that work too, but since it already feels like I'm on the wrong road since I can't fix the original 'card in deck/hand/etc' etc, I came here looking for some answers/tips.
Thanks for reading and I greatly appreciate any help you can give :)
--------------------- EDIT 1 *>
This is my current code: http://pastebin.com/g77Y4Tjr
--------------------- EDIT 2 *>
I've tried every single cmp advised here, and I still can't get it to find a card with 'in'.
>>> a = Card(0, 5)
>>> b = Card(0, 1)
>>> c = Card(3, 1)
>>> hand = Hand('Baris')
>>> hand.add(a)
>>> hand.add(b)
>>> hand.add(c)
>>> d = Card(3, 1)
>>> print(hand)
Hand Baris contains
5 of Clubs
Ace of Clubs
Ace of Spades
>>> d in hand.cards
False
>>>
I've also tried the card.py @DSM has used successfully, and I get errors there too, like at the sort function it says it cant compare the two card objects.
So I was wondering, maybe it is a problem with Python 3.2, or maybe the syntax has changed somewhere?
"So I was wondering, maybe it is a problem with Python 3.2, or maybe the syntax has changed somewhere?"
Oh, you're running Python 3.2? This'll never work in Python 3: python 3 doesn't use __cmp__!
See the data model (look for __eq__). Also read the what's new in Python 3 for some other things it's way too easy to miss.
Sorry, this is on us Python programmers here; we should have caught this far earlier. Most of probably looked at all the code, realized without even thinking about it that the source was obviously python 2 code, and assumed that's what we were working with. The cmp function doesn't even exist in Python 3.2, but the reason that it doesn't blow up with a NameError is because __cmp__ is never called.
If I run the code in Python 3.2, I reproduce your problem exactly:
>>> c = Card(0,2)
>>> str(c)
'2 of Clubs'
>>> c in [c]
True
>>> c in Deck().cards
False
In Python 3, you either implement all the rich cmps or __eq__ and one of them and use a total_ordering decorator.
from functools import total_ordering
@total_ordering
class Card(object):
"""Represents a standard playing card."""
suit_names = ["Clubs", "Diamonds", "Hearts", "Spades"]
rank_names = [None, "Ace", "2", "3", "4", "5", "6", "7",
"8", "9", "10", "Jack", "Queen", "King"]
def __init__(self, suit=0, rank=2):
self.suit = suit
self.rank = rank
def __str__(self):
return '%s of %s' % (Card.rank_names[self.rank],
Card.suit_names[self.suit])
def __repr__(self): return str(self)
def __lt__(self, other):
t1 = self.suit, self.rank
t2 = other.suit, other.rank
return t1 < t2
def __eq__(self, other):
t1 = self.suit, self.rank
t2 = other.suit, other.rank
return t1 == t2
>>> c = Card(2,3)
>>> c
3 of Hearts
>>> c in Deck().cards
True