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This small game is a simulation of a slot machine.
You can view or download the code here:
https://github.com/pythonbyexample/PBE/tree/master/code/slotmachine.py
To run SlotMachine, you will also need to download ‘utils.py’:
https://github.com/pythonbyexample/PBE/tree/master/code/utils.py
The Reel class represents a single reel, or ‘drum’, inside the machine, which rotates independently from other reels when the machine is running. It would be easy to make a random display of symbols while the reels are spinning and make a final random selection when it stops, but I think it’s more interesting to make a more realistic simulation and have the reels that are actually rotating in the same sequence. To make sure changing symbols of different reels are not synchronized, I’ll have them rotating at randomized, different speeds.
As in a real slot machine, I’ll stop the reels in a delayed order from left to right, using randomly generated max_cycle variable to let them know when to stop.
I’ll use the utils.Loop class to store the list of symbols and cycle through them using Loop.next() method. The symbol() method will rotate the reel if it did not reach max_cycle yet and return the current symbol:
class Reel(object):
def __init__(self, rotations, max_cycle):
self.reel = Loop(symbols.keys(), name="symbol")
self.rotations = rotations
self.max_cycle = max_cycle
def symbol(self, cycle=0):
if cycle and cycle <= self.max_cycle:
self.rotate()
return self.reel.symbol
def rotate(self): self.reel.next(self.rotations)
The run() method sets up the machine and runs it until all reels come to a stop.
I’ll need to create a rotation and max_cycle values for each of the reels and then create the reel objects themselves.
In the main loop itself I need to join all symbols into a line, display it and pause.
num_reels = 3
pause_time = 0.05
first_stop = 30 # stop first reel
reel_delay = 25 # range of delay to stop each reel
class SlotMachine(object):
def run(self, pause_time, display=True):
"""Run the machine, return tuple of (symbol line, win_amount)."""
rotations = [randint(1,4) for _ in range(num_reels)] # reel rotations per cycle
rd = reel_delay
total_cycles = [randint(x, x+rd) for x in range(first_stop, first_stop + rd*num_reels, rd)]
reels = [Reel(rotations, max_cycle) for rotations, max_cycle in zip(rotations, total_cycles)]
for cycle in range1(max(total_cycles)):
line = sjoin( [reel.symbol(cycle) for reel in reels] )
if display: print(nl*5, line)
sleep(pause_time)
return self.done(reels, display, line)
In the done() method, I have to check if all of the reels aligned with the same symbol by turning the line into a set (therefore eliminating duplicates) and checking if its length is 1:
def done(self, reels, display, line):
S = [r.symbol() for r in reels]
won = bool(len(set(S)) == 1)
amount = symbols[first(S)] if won else 0
if won and display:
print(winmsg % symbols[first(S)])
return line, amount
In the test mode, the machine will run 300 times without printing out the lines or pausing, at the end some statistics are added up and displayed. This is a good illustration of making a small program that may be reused by a different program (which may not want to print out all lines for each run).
def test():
slots = SlotMachine()
runs = [slots.run(0, False) for _ in range(300)]
wins = len([r for r in runs if r[1]])
total = sum(r[1] for r in runs)
showall = True
for run in runs:
if showall or run[1]:
print("%8s %6s" % run, nl)
print(" wins", wins)
print(" total", total)
You can change the symbols and related winnings, as well as a few other settings as described in the comments below:
num_reels = 3
pause_time = 0.05
first_stop = 30 # stop first reel
reel_delay = 25 # range of delay to stop each reel
winmsg = "You've won!! Collect your prize : %d"
symbols = {
'❄': 100,
'⌘': 200,
'✿': 500,
'❖': 1000,
'✬': 2500,
}
The winning rate is about 3%; here is the tail end of test() run:
❄ ❄ ❄ 100
❖ ⌘ ❖ 0
⌘ ⌘ ✿ 0
✿ ❄ ⌘ 0
❖ ⌘ ✿ 0
❖ ❖ ✿ 0
❄ ❄ ✿ 0
❄ ✿ ⌘ 0
wins 10
total 8300
Here is the test run with showall=False:
✿ ✿ ✿ 500
❖ ❖ ❖ 1000
⌘ ⌘ ⌘ 200
⌘ ⌘ ⌘ 200
❖ ❖ ❖ 1000
❖ ❖ ❖ 1000
wins 6
total 3900