Cards

Instantiation

To instantiate a Card, we can pass in a string:

Card("Kd")

Under the hood, this simply constructs the int representation of the card as the object:

assert Card("Kd") == 134236965

It is also possible to construct a card from the well-formed int form as described below:

assert str(Card(134236965)) == "Kd"

Representation

We represent Card objects as native Python 32-bit integers. Most of the bits are used, and have a specific meaning. See below:

Card

xxxbbbbb

bbbbbbbb

cdhsrrrr

xxpppppp

• p = prime number of rank (in binary) (deuce=2, trey=3, four=5, …, ace=41)

• r = rank of card (in binary) (deuce=0, trey=1, four=2, five=3, …, ace=12)

• cdhs = suit of card (bit turned on based on suit of card)

• b = bit turned on depending on rank of card (deuce=1st bit, trey=2nd bit, …)

• x = unused

Example

Card	xxxAKQJT	98765432	CDHSrrrr	xxPPPPPP
King of Diamonds	00001000	00000000	01001011	00100101
Five of Spades	00000000	00001000	00010011	00000111
Jack of Clubs	00000010	00000000	10001001	00011101

This representation allows for minimal memory overhead along with fast applications necessary for poker:

• Make a unique prime product for each hand (by multiplying the prime bits)

• Detect flushes (bitwise && for the suits)

• Detect straights (shift and bitwise &&)

Attributes

Following the representation from above, attributes of the card can be accessed through properties:

• rank

• suit

• bitrank

• prime

• str(card) for the string format (e.g. str(Card('Kd')) == 'Kd')

• pretty_string for a string with ascii suits.

Deck

The Deck class is a standard collection of the 52 possible Cards. Instantiate a new deck by simply calling it Deck(). The class provides one method draw() which takes an optional parameter n and returns that many Cards (default 1).

Card Collection Methods

In the card module, there is also a few helper functions that act on collections of cards.

This includes:

• card_strings_to_int() which transforms a list of strings like str(Card('Kd')) == 'Kd' into a list of the Card representations.

• prime_product_from_hand() which takes the prime product of a list of Cards.

• card_list_to_pretty_str() which returns a string which concatenates the pretty strings of each card.