Further-developed followup to this question

Python beginner here.

I created a command-line program that generates poker hands (5-52 cards) and compares their strength. On my Macbook Pro, it generates and compares 1m 5-card hands in ~2m.

Here's my code:

import copy
import distutils.core
from enum import Enum
from time import time
from random import shuffle
from math import floor

#Individual Cards
class Card:
    def __init__ (self,value,suit):
        self.value = value
        self.suit = suit
        self.vname = ''
        self.sname = ''

    def __str__(self):
        return f'{self.sname}{self.vname}{self.sname}'

    def __repr__(self):
        if self.value <= 10:
            return f'{self.value}{self.suit[0].lower()}'
        if self.value > 10:
            return f'{self.vname[0]}{self.suit[0].lower()}'

    def vsname(self,value,suit):
        if self.value == 2:
            self.vname = 'Two'
        elif self.value == 3:
            self.vname = 'Three'
        elif self.value == 4:
            self.vname = 'Four'
        elif self.value == 5:
            self.vname = 'Five'
        elif self.value == 6:
            self.vname = 'Six'
        elif self.value == 7:
            self.vname = 'Seven'
        elif self.value == 8:
            self.vname = 'Eight'
        elif self.value == 9:
            self.vname = 'Nine'
        elif self.value == 10:
            self.vname = 'Ten'
        elif self.value == 11:
            self.vname = 'Jack'
        elif self.value == 12:
            self.vname = 'Queen'
        elif self.value == 13:
            self.vname = 'King'
        elif self.value == 14:
            self.vname = 'Ace'

        if self.suit == "Hearts":
            self.sname = '♥'
        elif self.suit == "Spades":
            self.sname = '♠'
        elif self.suit == "Clubs":
            self.sname = '♣'
        elif self.suit == "Diamonds":
            self.sname = '♦︎︎'

#All Decks
class Deck:
    def __init__(self):
        self.cards = []

    def create(self):
        for _ in range(decks):
            for val in (2,3,4,5,6,7,8,9,10,11,12,13,14):
                for suit in ("Hearts", "Spades", "Clubs", "Diamonds"):

    def draw(self,x):
        for y in range(x):
            drawcards[y] = self.cards.pop()

        return drawcards

class BaseStrength(Enum):
    ROYAL_FLUSH = 10000
    QUADS = 8000
    FULL_HOUSE = 7000
    FLUSH = 6000
    STRAIGHT = 5000
    SET = 4000
    TWO_PAIR = 3000
    PAIR = 2000
    HIGH_CARD = 1000

#Determine Values and Suits in Hand
def determine(hand):
    values, vset, suits, all_cards = [], set(), [], []
    for x in range(len(hand)):
    return sorted(values,reverse=True),vset,suits,all_cards

#Message/Text Functions
def ss():
    if show_strength: print(f'[{round(strength/10000,6)}]')
    else: print()

def hnumber(max_v,msg):
    while True:
            hn = input(msg)
            if hn.lower() == 'm' or hn.lower() == 'max':
                return max_v
            elif 0 < int(hn) <= max_v:
                return int(hn)
                print(f'Please enter an integer between 1 and {max_v}.')
        except ValueError:
            print('Please enter a positive integer.')

def decks(msg):
    while True:
            d = int(input(msg))
            if d > 0:
                return d
                print('Please enter a positive integer.')
        except ValueError:
            print('Please enter a positive integer.')

def cph(msg):
    while True:
            d = int(input(msg))
            if 5 <= d <= 52:
                return d
                print('Please enter a positive integer between 5 and 52.')
        except ValueError:
            print('Please enter a positive integer between 5 and 52.')

def sstrength(msg):
    while True:
            ss = distutils.util.strtobool(input(msg))
            if ss == 0 or ss == 1:
                return ss
                print('Please indicate whether you\'d like to show advanced stats')
        except ValueError:
            print('Please indicate whether you\'d like to show advanced stats')

def get_inputs():
    decks_ = decks('How many decks are there? ')
    cph_ = cph('How many cards per hand? ')
    max_v = floor((decks_*52)/cph_)
    hnumber_ = hnumber(max_v,f'How many players are there (max {floor((decks_*52)/cph_)})? ')
    sstrength_ = sstrength("Would you like to show advanced stats? ")

    return (decks_,cph_,hnumber_,sstrength_)

def print_hand(user_hand):
    print(f"\nPlayer {h_inc + 1}'s hand:")
    print("| ",end="")
    for c_x in user_hand: print(user_hand[c_x],end=" | ")

def post_draw():
    hss = sorted(h_strength.items(), key=lambda k: k[1], reverse=True)

    if not show_strength:
        print(f'\n\n\nPlayer {hss[0][0] + 1} has the strongest hand!\nPlayer {hss[hnumber-1][0]+1} has the weakest hand :(')

    if show_strength:

        print(f'\n\n\nPlayer {hss[0][0]+1} has the strongest hand! [{round(hss[0][1]/10000,6)}]\nPlayer {hss[hnumber-1][0] + 1} has the weakest hand :( [{round(hss[hnumber-1][1]/10000,6)}]')

        print('\n\n\n\n\nHand Occurence:\n')
        for x in range(10): print(ho_names[x],hand_occurence[x],f'({round(100*hand_occurence[x]/len(hss),2)}%)')

        print('\n\n\n\n\nFull Player Ranking:\n')
        for x in range(len(hss)): print(f'{x+1}.',f'Player {hss[x][0]+1}',f'[{round(hss[x][1]/10000,6)}]')

        print('\n\n\nComplete Execution Time:', "%ss" % (round(time()-deck_start_time,2)))
        print('Deck Build Time:', '%ss' % (round(deck_end_time-deck_start_time,2)), f'({int(round(100*(deck_end_time-deck_start_time)/(time()-deck_start_time),0))}%)')
        print('Hand Build Time:', '%ss' % (round(time()-deck_end_time,2)), f'({int(round(100*(time()-deck_end_time)/(time()-deck_start_time),0))}%)')

#Evaluation Functions
def valname(x):
    if x == 2:
        return 'Two'
    elif x == 3:
        return 'Three'
    elif x == 4:
        return 'Four'
    elif x == 5:
        return 'Five'
    elif x == 6:
        return 'Six'
    elif x == 7:
        return 'Seven'
    elif x == 8:
        return 'Eight'
    elif x == 9:
        return 'Nine'
    elif x == 10:
        return 'Ten'
    elif x == 11:
        return 'Jack'
    elif x == 12:
        return 'Queen'
    elif x == 13:
        return 'King'
    elif x == 14 or x == 1:
        return 'Ace'

def hcard(values):
    global strength
    strength = BaseStrength.HIGH_CARD.value + 10*values[0] + values[1] + .1*values[2] + .01*values[3] + .001*values[4]
    return f'High-Card {valname(values[0])}'

def numpair(values):
    global strength
    pairs = list(dict.fromkeys([val for val in values if values.count(val) == 2]))
    if not pairs:
        return False
    if len(pairs) == 1:
        vp = values.copy()
        for _ in range(2):
        strength = BaseStrength.PAIR.value + 10*pairs[0] + vp[0] + .1*vp[1] + .01*vp[2];
        return f'Pair of {valname(pairs[0])}s'
    if len(pairs) >= 2:
        vps = values.copy()
        pairs = sorted(pairs,reverse=True)
        for _ in range(2):
            vps.remove(pairs[0]); vps.remove(pairs[1])
        strength = (BaseStrength.TWO_PAIR.value + 10*int(pairs[0]) + int(pairs[1])) + .1*vps[0]
        return f'{valname(pairs[0])}s and {valname(pairs[1])}s'

def trip(values):
    global strength
    trips = [val for val in values if values.count(val) == 3]
    if not trips:
        return False
        vs = values.copy()
        for _ in range(3):
        strength = BaseStrength.SET.value + 10*trips[0] + vs[0] + .1*vs[1]
        return f'Set of {valname(trips[0])}s'

def straight(vset,get_vals=False):
    global strength
    count = 0

    if not get_vals:
        straight = False
        for rank in (14, *range(2, 15)):
            if rank in vset:
                count += 1
                max_c = rank
                if count == 5:
                    strength = BaseStrength.STRAIGHT.value + 10*min(vset)
                    straight = f'Straight from {valname(max_c-4)} to {valname(max_c)}'
            else: count = 0
        return straight

    if get_vals:
        sset = set()
        for rank in (14, *range(2, 15)):
            if rank in vset:
                count += 1
                if count == 5:
                    return sset
                count = 0
                sset = set()
        raise Exception('No SSET')

def flush(suits,all_cards):
    global strength
    flushes = [suit for suit in suits if suits.count(suit) >= 5]
    if flushes: flushes_vals = sorted([card.value for card in all_cards if card.suit == flushes[0]],reverse=True)
    if not flushes:
        return False
        strength = BaseStrength.FLUSH.value + 10*flushes_vals[0] + flushes_vals[1] + .1*flushes_vals[2] + .01*flushes_vals[3] + .001*flushes_vals[4]
        flush = f'{valname(max(flushes_vals))}-High flush of {flushes[0]}'
    return flush

def fullhouse(values):
    global strength
    trips = list(dict.fromkeys(sorted([val for val in values if values.count(val) == 3],reverse=True)))
    if not trips:
        return False

    pairs = sorted([val for val in values if values.count(val) == 2],reverse=True)

    if pairs and trips:
        strength = BaseStrength.FULL_HOUSE.value + 10*trips[0] + pairs[0]
        fh = f'{valname(trips[0])}s full of {valname(pairs[0])}s'

    if len(trips) > 1:
        if pairs:
            if trips[1] > pairs[0]:
                strength = BaseStrength.FULL_HOUSE.value + 10*trips[0] + trips[1]
                fh = f'{valname(trips[0])}s full of {valname(trips[1])}s'
            strength = BaseStrength.FULL_HOUSE.value + 10*trips[0] + trips[1]
            fh = f'{valname(trips[0])}s full of {valname(trips[1])}s'

    if len(trips) == 1 and not pairs:
        return False

    return fh

def quads(values):
    global strength
    quads = [val for val in values if values.count(val) >= 4]
    if not quads:
        return False
        vq = values.copy()
        for _ in range(4): vq.remove(quads[0])
        strength = BaseStrength.QUADS.value + 10*quads[0] + vq[0]
        return f'Quad {valname(quads[0])}s'

def straightflush(suits,vset,all_cards):
    global strength
    straight_= False

    flushes = [suit for suit in suits if suits.count(suit) >= 5]
    if flushes:
        flushes_vals = sorted([card.value for card in all_cards if card.suit == flushes[0]],reverse=True)

        if straight(flushes_vals):
            straight_vals = straight(flushes_vals,True)
            if {14,10,11,12,13} <= straight_vals: straight_ = "Royal"
            if {14,2,3,4,5} <= straight_vals: straight_ = "Wheel"
            else: straight_ = "Normal"

    if straight_ == "Normal":
        strength = BaseStrength.STRAIGHT_FLUSH.value + 10*max(flushes_vals)
        sf = f'{valname(max(straight_vals))}-High Straight Flush of {flushes[0]}'
    elif straight_ == "Wheel":
        strength = BaseStrength.STRAIGHT_FLUSH.value
        sf = f'Five-High Straight Flush of {flushes[0]}'
    elif straight_ == "Royal":
        strength = BaseStrength.ROYAL_FLUSH.value
        sf = f'Royal Flush of {flushes[0]}'
        sf = False
    return sf

def evalhand(values,suits,vset,all_cards):
    x = straightflush(suits,vset,all_cards)
    if not x: x = quads(values)
    if not x: x = fullhouse(values)
    if not x: x = flush(suits,all_cards)
    if not x: x = straight(values)
    if not x: x = trip(values)
    if not x: x = numpair(values)
    if not x: x = hcard(values)

    return x

def count_hand_occurence(strength):
    if strength < 2000: hand_occurence[0]+=1
    elif strength < 3000: hand_occurence[1]+=1
    elif strength < 4000: hand_occurence[2]+=1
    elif strength < 5000: hand_occurence[3]+=1
    elif strength < 6000: hand_occurence[4]+=1
    elif strength < 7000: hand_occurence[5]+=1
    elif strength < 8000: hand_occurence[6]+=1
    elif strength < 9000: hand_occurence[7]+=1
    elif strength < 10000: hand_occurence[8]+=1
    elif strength == 10000: hand_occurence[9]+=1

hand_occurence = {0:0,1:0,2:0,3:0,4:0,5:0,6:0,7:0,8:0,9:0}
ho_names = ['High Card: ','Pair: ','Two-Pair: ','Three of a Kind: ','Straight: ','Flush: ','Full House: ','Four of a Kind: ','Straight Flush: ','Royal Flush: ']

drawcards, h_strength = {}, {}

decks, cards_per_hand, hnumber, show_strength = get_inputs()
deck_start_time = time()

deck = Deck()
deck_end_time = time()

#Hand Print Loop
for h_inc in range(hnumber):
    user_hand = deck.draw(cards_per_hand)

    values,vset,suits,all_cards = determine(user_hand)
    exact_hand = evalhand(values,suits,vset,all_cards)
    print('\n'+exact_hand,end=" "); ss()

    h_strength[h_inc] = strength


2 Answers 2

  • When you have a long if/elif chain in Python it's a good idea to use a dictionary instead. For example: {1: 'one', 2: 'two', 3: ...}. This also makes exception handling easier with the .get() method.

  • Try to use proper names rather than just x or y.

  • Instead of:

    for indx in range(len(some_list)):


    for item in some_list:
  • Follow colons with a new line.

  • The while True ... try ... except ValueError is a strange choice. Add a condition to your while loop and just increment some counter.

  • Don't use exceptions to control the flow of the program. Exceptions are for catching exceptional behaviour, i.e. when something has gone wrong.

  • Some of your lines are very long. Split up the printing if necessary.

  • Try to be consistent with fstrings or .format(), not old formatting style (%s).

  • Avoid using globals. There are various ways of getting rid of them such as wrapping hanging functions into a class and having the global as a class variable.

  • Wrap your "worker" code (the code that does all the calling) in a function called something like main() (ideally more descriptive than that). Then use the standard:

    if __name__ == '__main__':
  • Using a dictionary you can rewrite count_hand_occurance() to be a simple generator expression.

  • Try to add doctrings; as a minimum for the classes if not the functions/methods as well.

  • Consider logging all of these messages rather than printing them. Debugging is far easier with logged information. As a start, you could write a simple file writing function (open file in append mode, 'a+') that is called instead of print.

  • in post_draw() you have if not condition: followed by if condition:. Just use if, else.

  • More comments are needed in logic-dense areas.

Edit, some explanations

Using a dictionary instead of if/else, instead of:

if cond_a:
    return a
elif cond_b:
    return b
elif cond_c:
    return c

create a dictionary where the conditions are the keys, and the return variables are the values:

some_dict = {cond_a: a, cond_b: b, cond_c: c}

then when it comes to using it, just do:

return some_dict[condition]

You can also add a default value for when the conditions isn't handled by the dictionary: return some_dict.get(condition, default=None).

Class instead of globals:

The simplest example is to put the global into a class as you have done above with Deck:

class MyClass:

    def __init__(self, some_var):
        self.some_var = some_var

Then you can add your functions into that class as methods and they can all share self.some_var without putting it into the global scope.

There is almost always a way around using globals, try to narrow down exactly what you want to use the global for. Most of the time there'll be a design pattern to handle that case.

  • \$\begingroup\$ These are all good ideas. Could you explain in more depth how to do some of them? Like what would be the best way to turn the large if statements into dictionaries and what would be a better way to catch invalid input? Also, what would be the best way to get rid of the globale using class wrappers? \$\endgroup\$
    – Alec
    Mar 21, 2019 at 10:24
  • \$\begingroup\$ I've edited my comment with some explanations. \$\endgroup\$ Mar 21, 2019 at 11:20
  • \$\begingroup\$ I get an int has no attribute value error if I do for c in hand instead of for x in range(len(hand)) \$\endgroup\$
    – Alec
    Mar 21, 2019 at 23:35
  • \$\begingroup\$ for c in hand: values.append(c.value); vset.add(c.value); suits.append(c.suit); all_cards.append(c) doesn't work \$\endgroup\$
    – Alec
    Mar 21, 2019 at 23:36

In addition to what HoboProber already said in his answer, I would like to give you a little bit more feedback on the program logic itself.

For the purpose of evaluating the selected number of random card draws you pregenerate a huge amount of card decks, which takes up a lot of memory (when I was running your code for a large number of decks, it was in the order of several GB). You then go on to operate on this large set of card decks sequentially, drawing a few cards from each set, then check them and go on to the next set.

In reality you would usually have a single deck of cards, which you would shuffle randomly, then draw your hands, evaluate them, put them back and start all over again. I think, the same approach could be applied to your program as well. Doing it this way, you would save orders of magnitudes of memory and quite a lot of time spent on generating all the card decks. Since shuffling is already part of the program, there is no additional complexity.

If you would go on to work on your program/simulation and would like to improve the performance further, you could look into multiprocessing. The second approach would scale quite well since you can give every worker its on card deck to operate on, minimizing the need of synchronization while keeping the memory usage on a sane level. But before thinking about this in any way, save yourself a lot of headache and have a thorough look on what other reviewers already told you on this and the previous question.


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