Some time ago there was a post asking for help on a rock/paper/scissors
game. I read that thread at the time it was posted, but since it
received several answers I didn't pay too much attention to it. But I
can't find that thread again right now. However, the subject stuck
(loosely) in my mind, and it finally fermented enough that I wanted to
try writing a version myself.
My approach is very different from the original. It is based on the
fact that there are only nine possible combinations. I calculate a
value based on the combination (it's effectively calculating the value
of a ternary number) and use this value as an index into a tuple of
Results strings and a tuple of win/lose/draw codes.
Probably the least obvious and most confusing aspect is how I piece
together these output strings, using the new-style print formatting
syntax. The rest of the program should be pretty straight-forward.
I think it's fairly well commented.
Of course, I don't claim this to be optimum, or even necessarily a
good approach -- but it works. And I thought some people might find
it interesting look at and try.
(An irrelevant side-note: I wrote it on a Raspberry Pi.)
=========== <Code starts here> ==========
#!/usr/bin/env python3
# rps.py -- Rock, Paper, Scissors game
from random import choice
WIN = 0
LOSE = 1
DRAW = 2
def get_result(h, c):
"""Determine who wins this round,
return appropriate string and win/lose/draw code.
h: Human's selection (r, p or s)
c: Computer's selection (r, p or s)
"""
def val(c):
"""Convert charcter r, p or s to values 0, 1 or 2"""
return 'rps'.index(c)
# Strings used in results
rp = 'Paper covers Rock. {}'
rs = 'Rock smashes scissors. {}'
ps = 'Scissors cuts paper. {}'
ti = 'We both have {}. {}'
# Win/lose/draw codes
win = (DRAW, WIN, LOSE, LOSE, DRAW, WIN, WIN, LOSE, DRAW)
# Win/lose/draw strings
wins = ('You win', 'I win', "It's a draw")
# Results strings
res = (
ti.format('rocks', wins[DRAW]), # r-r
rp.format(wins[WIN]), # r-p
rs.format(wins[LOSE]), # r-s
rp.format(wins[LOSE]), # p-r
ti.format('paper', wins[DRAW]), # p-p
ps.format(wins[WIN]), # p-s
rs.format(wins[WIN]), # s-r
ps.format(wins[LOSE]), # s-p
ti.format('scissors', wins[DRAW]) # s-s
)
score = val(h) + 3 * val(c) # Calculate score
return res[score], win[score] # Result string & win code
def get_rps():
"""Get Rock/Paper/Scissor choice."""
while True:
select = input('\nDo you choose Rock, Paper or Scissors ').lower()
# Check for empty input or quit command
if not select or select in ['q', 'quit']:
return 'q' # Return quit code
# Check for valid input
if select in ['r', 'rock', 'p', 'paper', 's', 'scissors']:
return select[0] # Return first character
print('What did you say?? Try again please')
#================= Main Program starts here ==============
# Keep track of results:
# scores[0] = number of human wins
# scores[1] = number of computer wins
# scores[2] = number of draws
scores = [0] * 3
things = {'r':'a rock', 'p':'paper', 's':'scissors'}
print("Let's play a game or Rock, Paper, Scissors.\n")
print('Enter "r", "p", "s", "rock", "paper", or "scissors" for your choice.')
print('Use empty input, "q" or "quit" to end the game.')
while True:
computer = choice('rps') # Computer selects
human = get_rps() # Human selects
if human == 'q':
break
print('You have {}, I have {}. '.format(
things[human], things[computer]), end='')
res, scr = get_result(human, computer)
scores[scr] += 1 # Count win/lose/draw
print(res) # And show results
# Show final scores
print('\nTotal scores:')
print('\tYou won {} games'.format(scores[WIN]))
print('\tComputer won {} games'.format(scores[LOSE]))
print('\tThere were {} tie games'.format(scores[DRAW]))
print('\nThanks for playing with me. Bye now.')
========== <Code ends here> ==========
-=- Larry -=-
--
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