Python implements children's arithmetic games

Randomly select numbers and an arithmetic function to display the problem and verify the results. The result is given after 3 bad attempts, and will continue to run when the user enters a correct answer.

# -*- coding: utf-8 -*-from operator import add, sub                   #从  operator  and  random  module, import the functions we will use        from random import  randint, choiceops = {' + ': add,  '-': sub}                      #定义全局变量   A collection that contains the operators and the functions associated with them (dictionary) maxtaries = 3                                    #定义全局变量   How many times the user has the opportunity to try to give an answer to an integer variable Def doprob ():                                       #定义此程序的核心程序     op = choice (' +-')                                #随机选择一个操作     nums = [ Randint (1, 10)  for i in range (2)]     #随机生成两个操作数      nums.sort (reverse=true)                         #为了避免减法问题中的负数问题, sort the two operands down to the next      ANS = OPS[OP] (*nums)                            #调用一个数学函数计算出正确的解      pr =  '%d %s %d = '  %  (nums[0], op, nums[1])      #生成   Prompts the user to calculate the equation     oops = 1                                        #定义   Counters for user-attempted opportunities     while True:         try:             if int (Raw_input (pr))  == ans:         #判断   User-entered answers and   correct answers compare                  print  ' correct '                     #输出提示信息                  break                              #退出循环              if oops == maxtaries:                  #当用户尝试次数等于用户最大尝试次数时                  print  ' answer\n%s%d '% (Pr,ans)       #将等式和   Correct answer output                  break             else:                                   #在其他情况下                  print  ' incorrect...  Try again '    #输出提示信息                 oops  += 1                          #用户尝试机会的计数器加一          except (Keyboardinterrupt, eoferror, valueerror):          #捕捉用户的错误输出             print  ' invalid  input... try again '     #输出提示信息def  main ():     while  true:        doprob ()                                   #调用核心函数         try:         &Nbsp;   opt = raw_input (' again?[ Y] '). Lower ()      #读取用户输入的参数   Lowercase If it is uppercase              if opt and opt[0] ==  ' n ':                 #当用户输入n   or  N  exit user cycle                  break         except (Keyboardinterrupt, eoferror):             breakif __name__ ==  ' __main__ ':     main ()

Python implements children's arithmetic games