检查列表是否包含4个相同值的元素

Question

So I'm stuck on a newbie problem once more :D

I'm trying to mash together a text based game of go-fish against the computer.

Ok so 1 card is actually a tuple of elements from two lists.

suits = ['Clubs', 'Diamonds', 'Spade', 'Hearts']
ranks = [None, 'ace', '2', '3', '4', '5', '6', '7', '8', '9', '10', 'jack', 'queen', 'king']

Then that is added to a deck and shuffled and whatnot and then dealt into hands. (got most of it from the book thinkpython i think. Learned a lot about class structure and inheritance in the process.)

So one hand might look like this

['Clubs 2', 'Diamonds king', 'Diamonds 2', 'Spades 2', 'Hearts 2']

As you can see that hand contains four of the same rank so that's 1 point for the player. But how would I check if the hand contains four instances of any item in the ranks list? Do I have to iterate through each item in the list or there some clean and simple way to it?

---

EDIT
Thanks a lot for all the answers guys. :D But I'm getting an attribute error when I try to use 'split' on the items in the hand. Guess I should have posted more of the code I'm running.

Full code and traceback here
http://pastebin.com/TwHkrbED

Is there something wrong with how the methods are defined in Card? I've been hacking around for hours trying to make it work, but no luck.

EDIT2
Made some changes to the deck generating part. Now the whole deck is a list of tuples and a lot less code.

thedeck=[]
class Deckofcards:
    suits = ['Clubs', 'Diamonds', 'Hearts', 'Spades']
    ranks = ['Ace', '2', '3', '4', '5', 
        '6', '7', '8', '9', '10', 'Jack', 'Queen', 'King']
    def __init__(self):
        for i in self.suits:
            for a in self.ranks:
                thedeck.append((i, a))

Seems like the other way was overly complicated, but idk. I'll see how it goes tomorrow, adding the actual game parts.

Answer 1

I might suggest a slight refactoring: Represent each card in a hand as a tuple of (rank, suit) . So your example hand would be:

hand = [('2', 'Clubs'),
        ('king', 'Diamonds'),
        ('2', 'Diamonds'),
        ('2', 'Spades'),
        ('2', 'Hearts')]

Then I'd suggest a couple of auxiliary functions to help you determine the value of a hand:

from collections import defaultdict

def get_counts(hand):
    """Returns a dict mapping card ranks to counts in the given hand."""
    counts = defaultdict(int)
    for rank, suit in hand:
        counts[rank] += 1
    return counts

def get_points(hand):
    """Returns the number of points (ie, ranks with all 4 cards) in the given
    hand."""
    return sum(1 for count in get_counts(hand).itervalues() if count == 4)

Edit: Switched to using sum in the get_points function, which seems clearer to me.

Working with these functions and the example hand you gave, you get output like so:

>>> get_counts(hand)
defaultdict(<type 'int'>, {'king': 1, '2': 4})

>>> get_points(hand)
1

Answer 2

Here's one way:

x = ['Clubs 2', 'Diamonds king', 'Diamonds 2', 'Spades 2', 'Hearts 2']
ranks = [i.split()[1] for i in x]
fourofakind = any(ranks.count(i)==4 for i in set(ranks))

fourofakind is then True if there are four cards of the same rank in the hand.

Answer 3

If you are looking for an extended kind of functionality:

hand = ['Clubs 2', 'Diamonds king', 'Diamonds 2', 'Spades 2', 'Hearts 2']
hand_ranks = [i.split()[1] for i in x]
fourofakind = {}
for i in set(hand_ranks):
    fourofakind[i] = (hand_ranks.count(i) == 4)

Would give you a dict() mapping card rank (of cards in the hand) to whether you have 4 of that rank.

Answer 4

A bit more general than Justin's:

suits = ['Clubs', 'Diamonds', 'Spade', 'Hearts']
ranks = [None, 'ace', '2', '3', '4', '5', '6', '7', \
'8', '9', '10', 'jack', 'queen', 'king']

hand = ['Clubs 2', 'Diamonds king', 'Diamonds 2', 'Spades 2', 'Hearts king']
rankshand = [i.split()[1] for i in hand]

fourofakind = [hr for hr in ranks if rankshand.count(hr)==4]
threeofakind = [hr for hr in ranks if rankshand.count(hr)==3]
pair = [hr for hr in ranks if rankshand.count(hr)==2]

fourofakind
[]
threeofakind
['2']
pair
['king']

With the ability to see which rank has the set.

Answer 5

The new built-in Counter class added in Python 2.7 to the standard library collections module makes this fairly easy.

suits = ['Clubs', 'Diamonds', 'Spade', 'Hearts']
ranks = [None, 'ace', '2', '3', '4', '5', '6', '7',
         '8', '9', '10', 'jack', 'queen', 'king']
hand = ['Clubs 2', 'Diamonds king', 'Diamonds 2', 'Spades 2', 'Hearts 2']

from collections import Counter

counts = Counter(card.split()[1] for card in hand)
four_of_a_kind = [rank for rank,count in counts.iteritems() if count == 4]
print 'four_of_a_kind:', four_of_a_kind
# four_of_a_kind: ['2']