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to Poker in the Python Track

Published at Jul 13 2018 · 0 comments
Instructions
Test suite
Solution

Note:

This solution was written on an old version of Exercism. The tests below might not correspond to the solution code, and the exercise may have changed since this code was written.

Pick the best hand(s) from a list of poker hands.

See wikipedia for an overview of poker hands.

Exception messages

Sometimes it is necessary to raise an exception. When you do this, you should include a meaningful error message to indicate what the source of the error is. This makes your code more readable and helps significantly with debugging. Not every exercise will require you to raise an exception, but for those that do, the tests will only pass if you include a message.

To raise a message with an exception, just write it as an argument to the exception type. For example, instead of raise Exception, you should write:

raise Exception("Meaningful message indicating the source of the error")

Running the tests

To run the tests, run the appropriate command below (why they are different):

  • Python 2.7: py.test poker_test.py
  • Python 3.4+: pytest poker_test.py

Alternatively, you can tell Python to run the pytest module (allowing the same command to be used regardless of Python version): python -m pytest poker_test.py

Common pytest options

  • -v : enable verbose output
  • -x : stop running tests on first failure
  • --ff : run failures from previous test before running other test cases

For other options, see python -m pytest -h

Submitting Exercises

Note that, when trying to submit an exercise, make sure the solution is in the $EXERCISM_WORKSPACE/python/poker directory.

You can find your Exercism workspace by running exercism debug and looking for the line that starts with Workspace.

For more detailed information about running tests, code style and linting, please see the help page.

Source

Inspired by the training course from Udacity. https://www.udacity.com/course/viewer#!/c-cs212/

Submitting Incomplete Solutions

It's possible to submit an incomplete solution so you can see how others have completed the exercise.

poker_test.py

import unittest

from poker import best_hands


# Tests adapted from `problem-specifications//canonical-data.json` @ v1.1.0

class PokerTest(unittest.TestCase):
    def test_single_hand_always_wins(self):
        hands = ["4S 5S 7H 8D JC"]
        expected = ["4S 5S 7H 8D JC"]
        self.assertEqual(best_hands(hands), expected)

    def test_highest_card_out_of_all_hands_wins(self):
        hands = [
            "4D 5S 6S 8D 3C",
            "2S 4C 7S 9H 10H",
            "3S 4S 5D 6H JH",
        ]
        expected = ["3S 4S 5D 6H JH"]
        self.assertEqual(best_hands(hands), expected)

    def test_tie_has_multiple_winners(self):
        hands = [
            "4D 5S 6S 8D 3C",
            "2S 4C 7S 9H 10H",
            "3S 4S 5D 6H JH",
            "3H 4H 5C 6C JD",
        ]
        expected = [
            "3S 4S 5D 6H JH",
            "3H 4H 5C 6C JD",
        ]
        self.assertEqual(best_hands(hands), expected)

    def test_tie_compares_multiple(self):
        hands = [
            "3S 5H 6S 8D 7H",
            "2S 5D 6D 8C 7S",
        ]
        expected = ["3S 5H 6S 8D 7H"]
        self.assertEqual(best_hands(hands), expected)

    def test_one_pair_beats_high_card(self):
        hands = [
            "4S 5H 6C 8D KH",
            "2S 4H 6S 4D JH",
        ]
        expected = ["2S 4H 6S 4D JH"]
        self.assertEqual(best_hands(hands), expected)

    def test_highest_pair_wins(self):
        hands = [
            "4S 2H 6S 2D JH",
            "2S 4H 6C 4D JD",
        ]
        expected = ["2S 4H 6C 4D JD"]
        self.assertEqual(best_hands(hands), expected)

    def test_two_pairs_beats_one_pair(self):
        hands = [
            "2S 8H 6S 8D JH",
            "4S 5H 4C 8C 5C",
        ]
        expected = ["4S 5H 4C 8C 5C"]
        self.assertEqual(best_hands(hands), expected)

    def test_two_double_pair(self):
        hands = [
            "2S 8H 2D 8D 3H",
            "4S 5H 4C 8S 5D",
        ]
        expected = ["2S 8H 2D 8D 3H"]
        self.assertEqual(best_hands(hands), expected)

    def test_two_double_pair_higher_tie(self):
        hands = [
            "2S QS 2C QD JH",
            "JD QH JS 8D QC",
        ]
        expected = ["JD QH JS 8D QC"]
        self.assertEqual(best_hands(hands), expected)

    def test_two_double_pair_tie_kicker(self):
        hands = [
            "JD QH JS 8D QC",
            "JS QS JC 2D QD",
        ]
        expected = ["JD QH JS 8D QC"]
        self.assertEqual(best_hands(hands), expected)

    def test_three_of_a_kind_beats_two_pair(self):
        hands = [
            "2S 8H 2H 8D JH",
            "4S 5H 4C 8S 4H",
        ]
        expected = ["4S 5H 4C 8S 4H"]
        self.assertEqual(best_hands(hands), expected)

    def test_two_triple_pair(self):
        hands = [
            "2S 2H 2C 8D JH",
            "4S AH AS 8C AD",
        ]
        expected = ["4S AH AS 8C AD"]
        self.assertEqual(best_hands(hands), expected)

    def test_two_three_multiple_decks(self):
        hands = [
            "4S AH AS 7C AD",
            "4S AH AS 8C AD",
        ]
        expected = ["4S AH AS 8C AD"]
        self.assertEqual(best_hands(hands), expected)

    def test_three_vs_straight(self):
        hands = [
            "4S 5H 4C 8D 4H",
            "3S 4D 2S 6D 5C",
        ]
        expected = ["3S 4D 2S 6D 5C"]
        self.assertEqual(best_hands(hands), expected)

    def test_aces_can_end_straight(self):
        hands = [
            "4S 5H 4C 8D 4H",
            "10D JH QS KD AC",
        ]
        expected = ["10D JH QS KD AC"]
        self.assertEqual(best_hands(hands), expected)

    def test_aces_can_start_straight(self):
        hands = [
            "4S 5H 4C 8D 4H",
            "4D AH 3S 2D 5C",
        ]
        expected = ["4D AH 3S 2D 5C"]
        self.assertEqual(best_hands(hands), expected)

    def test_two_straights(self):
        hands = [
            "4S 6C 7S 8D 5H",
            "5S 7H 8S 9D 6H",
        ]
        expected = ["5S 7H 8S 9D 6H"]
        self.assertEqual(best_hands(hands), expected)

    def test_lowest_straight(self):
        hands = [
            "2H 3C 4D 5D 6H",
            "4S AH 3S 2D 5H",
        ]
        expected = ["2H 3C 4D 5D 6H"]
        self.assertEqual(best_hands(hands), expected)

    def test_straight_vs_flush(self):
        hands = [
            "4C 6H 7D 8D 5H",
            "2S 4S 5S 6S 7S",
        ]
        expected = ["2S 4S 5S 6S 7S"]
        self.assertEqual(best_hands(hands), expected)

    def test_two_flushes(self):
        hands = [
            "4H 7H 8H 9H 6H",
            "2S 4S 5S 6S 7S",
        ]
        expected = ["4H 7H 8H 9H 6H"]
        self.assertEqual(best_hands(hands), expected)

    def test_flush_vs_full(self):
        hands = [
            "3H 6H 7H 8H 5H",
            "4S 5H 4C 5D 4H",
        ]
        expected = ["4S 5H 4C 5D 4H"]
        self.assertEqual(best_hands(hands), expected)

    def test_two_fulls(self):
        hands = [
            "4H 4S 4D 9S 9D",
            "5H 5S 5D 8S 8D",
        ]
        expected = ["5H 5S 5D 8S 8D"]
        self.assertEqual(best_hands(hands), expected)

    def test_two_fulls_same_triplet(self):
        hands = [
            "5H 5S 5D 9S 9D",
            "5H 5S 5D 8S 8D",
        ]
        expected = ["5H 5S 5D 9S 9D"]
        self.assertEqual(best_hands(hands), expected)

    def test_full_vs_four(self):
        hands = [
            "4S 5H 4D 5D 4H",
            "3S 3H 2S 3D 3C",
        ]
        expected = ["3S 3H 2S 3D 3C"]
        self.assertEqual(best_hands(hands), expected)

    def test_two_fours(self):
        hands = [
            "2S 2H 2C 8D 2D",
            "4S 5H 5S 5D 5C",
        ]
        expected = ["4S 5H 5S 5D 5C"]
        self.assertEqual(best_hands(hands), expected)

    def test_two_fours_kicker(self):
        hands = [
            "3S 3H 2S 3D 3C",
            "3S 3H 4S 3D 3C",
        ]
        expected = ["3S 3H 4S 3D 3C"]
        self.assertEqual(best_hands(hands), expected)

    def test_four_vs_straight_flush(self):
        hands = [
            "4S 5H 5S 5D 5C",
            "7S 8S 9S 6S 10S",
        ]
        expected = ["7S 8S 9S 6S 10S"]
        self.assertEqual(best_hands(hands), expected)

    def test_two_straight_flushes(self):
        hands = [
            "4H 6H 7H 8H 5H",
            "5S 7S 8S 9S 6S",
        ]
        expected = ["5S 7S 8S 9S 6S"]
        self.assertEqual(best_hands(hands), expected)


if __name__ == '__main__':
    unittest.main()
STRAIGHT_FLUSH = 800
FOUR_OF_A_KIND = 700
FULL_HOUSE = 600
FLUSH = 500
STRAIGHT = 400
THREE_OF_A_KIND = 300
TWO_PAIR = 200
ONE_PAIR = 100
HIGH_CARD = 0


class Poker:
    def __init__(self, hands):
        self.hands = [Hand(hand) for hand in hands]

    def best_hand(self):
        return [hand.hand for hand, score in self.scores().items() if score ==
                self.best_score()]

    def best_score(self):
        return max(self.scores(), key=self.scores().get).score()

    def scores(self):
        return {hand: hand.score() for hand in self.hands}


class Hand:
    def __init__(self, hand):
        self.hand = hand
        self.cards = [Card(card) for card in hand]
        self.ranks = [card.rank for card in self.cards]
        self.suits = [card.suit for card in self.cards]

    def score(self):
        if self.straight_flush():
            return STRAIGHT_FLUSH + self.high_card()
        elif self.four_of_a_kind():
            return FOUR_OF_A_KIND + self.rank_of_card_with_highest_occurence()
        elif self.full_house():
            return FULL_HOUSE + self.rank_of_card_with_highest_occurence()
        elif self.flush():
            return FLUSH + self.high_card()
        elif self.straight():
            return STRAIGHT + self.high_card()
        elif self.three_of_a_kind():
            return THREE_OF_A_KIND + self.rank_of_card_with_highest_occurence()
        elif self.two_pair():
            return TWO_PAIR + self.high_card()
        elif self.one_pair():
            return ONE_PAIR + self.rank_of_card_with_highest_occurence()
        else:
            return self.high_card()

    def straight_flush(self):
        return self.straight() and self.flush()

    def straight(self):
        return (range(min(self.ranks), max(self.ranks) + 1) ==
                sorted(self.ranks))

    def flush(self):
        return len(set(self.suits)) == 1

    def four_of_a_kind(self):
        return max(self.rank_occurences().values()) == 4

    def full_house(self):
        return self.three_of_a_kind() and self.one_pair()

    def three_of_a_kind(self):
        return 3 in self.rank_occurences().values()

    def two_pair(self):
        return 2 == self.rank_occurences().values().count(2)

    def one_pair(self):
        return 2 in self.rank_occurences().values()

    def high_card(self):
        return max(self.ranks)

    def rank_occurences(self):
        return {rank: self.ranks.count(rank) for rank in self.ranks}

    def rank_of_card_with_highest_occurence(self):
        return max(self.rank_occurences(), key=self.rank_occurences().get)


class Card:
    FACE_CARDS = {"T": 10,
                  "J": 11,
                  "Q": 12,
                  "K": 13,
                  "A": 14}

    def __init__(self, inp):
        self.rank = self.numberify_face_cards(inp[0])
        self.suit = inp[1]

    def __str__(self):
        return str(self.rank) + self.suit

    @classmethod
    def numberify_face_cards(cls, rank):
        if rank in cls.FACE_CARDS.keys():
            return cls.FACE_CARDS[rank]
        return int(rank)


def poker(inp):
    return Poker(inp).best_hand()

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