indefinite

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

Source code:

import random

wbt = {"R":"P","P":"S","S":"R"}

def move(my,th):
    if len(my) < 1:
        return 'S'
    pat = []
    cu = my[-1]+th[-1]
    for i in range(len(my)-1):
        c = my[i]+th[i]
        if c == cu:
            pat.append(th[i+1])
    if len(pat) > 0:
        return wbt[random.choice(pat)]
    else:
        return wbt[th[random.randint(0,len(th)-1)]]

if input == "":
    m = ""
    t = ""
else:
    t +=input
x = move(m,t)
m+=x
output = x