ProjectX

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

Source code:

if not input:
    import random
    from collections import defaultdict
    memory = {2:defaultdict(lambda: {'R':0,'P':0,'S':0}), 3:defaultdict(lambda: {'R':0,'P':0,'S':0}), 4:defaultdict(lambda: {'R':0,'P':0,'S':0})}    
    history=""
    random.seed()

weights = {'R':0,'P':0,'S':0}

for index,counts in memory.iteritems():
    if len(history)<(index):
        continue
    counts[history[-index:]][input]+=1

history+=input

for index,counts in memory.iteritems():
    if len(history)<(index):
        continue
    for k,v in counts[history[-index:]].iteritems():
        weights[k]+=v

totw=sum(weights.values())
if not totw:
    totw=3
    weights={'R':1,'P':1,'S':1}

decision = random.uniform(0,totw)
for k,v in weights.iteritems():
    decision-=v
    if decision<=0:
        output=k
        break
output = ['R','P','S'][({'R':0,'P':1,'S':2}[output]+1)%3]