TestBot

Use rpsrunner.py to play unranked matches on your computer.

Source code:

import random

def most_likely(history):
    if history != []:
        d = {"R": history.count("R"), "P": history.count("P"), "S": history.count("S")}
        return max(d, key=d.get)

def opposite(move):
    if move == "R":
        return "P"
    elif move == "P":
        return "S"
    else:
        return "R"

def updateStats(myMove, theirMove, results):
    if (myMove == "R" and theirMove == "S" or
        myMove == "P" and theirMove == "R" or
        myMove == "S" and theirMove == "P"):
        results[0] += 1
    elif myMove == theirMove:
        results[2] += 1
    else:
        results[1] += 1

def winPercentage(results):
    if results[0] == 0:
        print results[0]
        return 0
    elif results[1] == 0:
        return 100
    return (float(results[0]) / (results[0] + results[1])) * 100

choices = ["R", "P", "S"]

if input == "":
    my_history = []
    their_history = []
    results = [0, 0, 0]
    output = random.choice(choices)
elif input in choices:
    if my_history and their_history:
        updateStats(my_history[len(my_history) - 1], their_history[len(their_history) - 1], results)

    their_history.append(input)

    smart_choice = opposite(opposite(most_likely(my_history)))
    counter_choice = opposite(most_likely(their_history))

    random_choice = random.choice(choices)
    output = smart_choice if (random.random() >= 0.3) else counter_choice

    my_history.append(output)