python加减乘除，格式化字符串

#!/usr/bin/pythonnum1 = input("Please input a number:")
num2 = input("Please input a number:")print num1 + num2
print num1 - num2print num1 * num2print num1 / num2print "%s + %s = %s" % (num1, num2, num1 + num2)print "%s - %s = %s" % (num1, num2, num1 - num2)print "%s * %s = %s" % (num1, num2, num1 * num2)print "%s / %s = %s" % (num1, num2, num1 / num2)

/除//取整%取余**乘方

#!/usr/bin/env python

from operator import add, sub,mul,div, imod

from random import randint, choice

ops = {'+': add, '-': sub, '*': mul, '/': div}
ops1 = {'+': add, '-': sub, '*': mul}
MAXTRIES = 2
def doprob():
nums = [randint(1,10) for i in range(2)]
nums.sort(reverse=True)
if imod(*nums) == 0:
op = choice('+-*/')
ans=ops[op](*nums)
else:
op = choice('+-*')
ans=ops1[op](*nums)
pr='%d %s %d =' % (nums[0],op,nums[1])
oops = 0
while True:
try:
if int(raw_input(pr))==ans:
print 'correct!'
break
if oops == MAXTRIES:
print 'answer \n%s%d' %(pr,ans)
else:
print 'incorrect... try again'
oops+=1
except(KeyboardInterrupt,EOFError,ValueError):
print 'invalid input... try again'
def main():
while True:
doprob()
try:
opt = raw_input('again?[y]').lower()
if opt and opt[0]=='n':
break
except (KeyboardInterrupt,EOFError):
break
if __name__=='__main__':
main()