宝宝加减法出题小程序

避免计算过程中出现负数，可以设定题目长度，最大的数字。

"""
Spyder Editor

This is a temporary script file.
"""
import random
import re
import pprint


def calc(s = '5+6-1'):
    '''
    @s:'5+6-1'
    '''
    #print 'calc : %s 
' % s
    numbers = re.findall(r'd+' , s)
    symbols = re.findall(r'[+-]+', s)
    i = 1
    j = 0
    result = 0
    result += int(numbers[0])
    while i < len(numbers) and j < len(symbols):
        if symbols[j] == '+' :
            result += int(numbers[i])
        elif symbols[j] == '-' :
            result -= int(numbers[i])
        else:
            print symbols
            print 'Only + and - accept'
            return False
        i += 1
        j += 1 
        if result < 0:
            #print 'negtive not accept'
            return False
    #print '%s = %d' %(s,result)
    return result

def getOneExpression(problemMaxLength = 5 , maxNum = 15):
    problemLength = random.randint(2,problemMaxLength)
    expression = ''
    i = 0
    num = random.randint(0 , maxNum)
    expression += str(num)
    while i < problemLength-1:
        tmp = expression
        expression += random.sample(['+','-'] , 1)[0]
        num = random.randint(0 , maxNum)
        expression += str(num)
        #print 'expression1 : ' ,expression
        if calc(expression):
            i += 1
        else:
            expression = tmp
        #print 'expression2 : ' ,expression
        #import time
        #time.sleep(1)
    #print expression
    return expression

def setProblems(problemNum = 10 , problemMaxLength = 5 , maxNum = 15):
    problem = {}#{'P1':{'problem':'5+6' , result = 11}}
    
    # set level
    #problemNum = 10
    #problemMaxLength = 5
    #maxNum = 15
    for i in range(problemNum): 
        problem.setdefault('P'+str(i) , {})
        problem['P'+str(i)].setdefault('problem' , 
                getOneExpression(problemMaxLength , maxNum))
        
        problem['P'+str(i)].setdefault('result' , 
                calc(problem['P'+str(i)]['problem']))        
    return problem

#test 
'''      
calc('1')
getOneExpression()
random.sample(['+','-'] , 1)
'''

problems = setProblems()
pprint.pprint(problems)