Python 函数练习数字游戏

#!/usr/bin/env python

import random
import sys

def add(x,y):
   return x + y

def sub(x,y):
    return  x - y

def probe():
    CMDs = {‘+‘:add,‘-‘:sub}
    alist = [random.randint(1,50) for i in range(2)]
    alist.sort(reverse=True)
    op = random.choice(CMDs.keys())
    answer = CMDs[op](*alist)
    prompt = """%s %s %s:""" %(alist[0],op,alist[1])

    i = 0

    while i < 3:
        try:
            result = int(raw_input(prompt))
        except (KeyboardInterrupt,EOFError),e:
            print "\nUser cancelled"
            sys.exit()
        except (ValueError,IndexError,UnboundLocalError):
            print "Invaild"
        if answer == result:
            print "very good"
            break
        print "input wrong still %d chance" % (2-i)
        i += 1
    else:
        print ("%s%s") % (prompt,answer)

if __name__ == ‘__main__‘:
    while True:
        probe()
        yn = raw_input("continue(y/n)?>:".strip()[0])
        if yn in ‘Nn‘:
            print "bye-bye"
            break