作业五：RE 模块模拟计算器

# !/usr/bin/env python3
# _*_coding:utf-8_*_
\'\'\'
实现模拟计算器的功能：
公式：1 - 2 * ( (60-30 +(-40/5) * (9-2*5/3 + 7 /3*99/4*2998 +10 * 568/14 )) - (-4*3)/ (16-3*2) )
思路：
括号的计算优先级最高，应该优先计算括号内的式子，然后将值代替会原式子，循环，接着做惩处运算，最后是加减运算，然后弹出结果，
# print(eval(\'1-2*((60-30+(-40/5)*(9-2*5/3+7/3*99/4*2998+10*568/14))-(-4*3)/(16-3*2))\'))
\'\'\'
import re

symbol = [\'0\', \'1\', \'2\', \'3\', \'4\', \'5\', \'6\', \'7\', \'8\', \'9\', \'-\', \'+\', \'*\', \'/\', \'(\', \')\']


def check(formula):
    \'\'\'
    检查输入的公式的正确性：
    除了十个数字和六个符号，其他的一律判错，但是这样会限制运算规则，目前先是这样规划
    :param formula:
    :return:
    \'\'\'
    symbol_flag = True
    formula = re.sub(r\'\s*\', \'\', formula)
    cal_list = list(formula)
    for item in cal_list:
        if item not in symbol:
            symbol_flag = False
    if not symbol_flag:
        return 1
    else:
        return formula


def change(formula):
    \'\'\'
    替换出现两个运算符在一起的情况：
    :param formula:
    :return:
    \'\'\'
    formula = formula.replace(\'--\', \'+\')
    formula = formula.replace(\'++\', \'+\')
    formula = formula.replace(\'**\', \'*\')
    formula = formula.replace(\'//\', \'=\')
    formula = formula.replace(\'*+\', \'*\')
    formula = formula.replace(\'/+\', \'/\')
    return formula


def chengchu(arg):
    val = arg[0]
    match = re.search(r\'\d+\.*\d*[\*\/]+[\+\-]?\d+\.*\d*\', val)
    if not match:
        return

    content = re.search(r\'\d+\.*\d*[\*\/]+[\+\-]?\d+\.*\d*\', val).group()
    if len(content.split(\'*\')) > 1:
        n1, n2 = content.split(\'*\')
        value = float(n1) * float(n2)
    else:
        n1, n2 = content.split(\'/\')
        value = float(n1) / float(n2)

    before, after = re.split(r\'\d+\.*\d*[\*\/]+[\+\-]?\d+\.*\d*\', val, 1)
    new_str = \'%s%s%s\' % (before, value, after)
    arg[0] = new_str
    print(arg)
    chengchu(arg)


def jiajian(arg):
    while True:
        if arg[0].__contains__(\'+-\') or arg[0].__contains__("++") or arg[0].__contains__(\'-+\') or arg[0].__contains__(
                "--"):
            arg[0] = arg[0].replace(\'++\', \'+\')
            arg[0] = arg[0].replace(\'+-\', \'-\')
            arg[0] = arg[0].replace(\'--\', \'+\')
            arg[0] = arg[0].replace(\'-+\', \'-\')
        else:
            break

    if arg[0].startswith(\'-\'):
        arg[1] += 1
        arg[0] = arg[0].replace(\'-\', \'&\')
        arg[0] = arg[0].replace(\'+\', \'-\')
        arg[0] = arg[0].replace(\'&\', \'+\')
        arg[0] = arg[0][1:]

    val = arg[0]

    match = re.search(r\'\d+\.?\d*[-+]{1}\d+\.?\d*\', val)
    if not match:
        return

    content = re.search(r\'\d+\.?\d*[-+]{1}\d+\.?\d*\', val).group()

    if len(content.split(\'+\')) > 1:
        n1, n2 = content.split(\'+\')
        value = float(n1) + float(n2)
    else:
        n1, n2 = content.split(\'-\')
        value = float(n1) - float(n2)

    before, after = re.split(r\'\d+\.?\d*[-+]{1}\d+\.?\d*\', val, 1)
    new_str = \'%s%s%s\' % (before, value, after)
    arg[0] = new_str
    jiajian(arg)


def compute(formula):
    \'\'\'
    操作加减乘除：根据操作
    :param formula:
    :return:
    \'\'\'
    inp = [formula, 0]  #
    chengchu(inp)
    jiajian(inp)
    if divmod(inp[1], 2)[1] == 1:
        result = float(inp[0])
        result = float(result) * -1
    else:
        result = float(inp[0])
    return result


def calcultor(formula):
    \'\'\'
    递归处理括号，并计算括号内的式子，将结果返回做替换，
    :param formula:
    :return:
    \'\'\'
    # 没有括号了
    if not re.search(r\'\(([-+*/]*\d+\.*\d*){2,}\)\', formula):
        final = compute(formula)
        return final
    # 取出其中的一个括号，然后计算
    content = re.search(r\'\(([-+*/]*\d\.*\d*){2,}\)\', formula).group()
    # 分裂表达式
    before, nothing, after = re.split(r\'\(([-+*/]*\d+\.*\d*){2,}\)\', formula, 1)
    # 计算括号里的内容
    content = content[1:len(content) - 1]
    ret = compute(content)
    # 计算完后然后拿到结果，然后重新拼接成一个新的式子
    formula = \'%s%s%s\' % (before, ret, after)
    return calcultor(formula)


# s=\'1-2*((60-30+(-40/5)*(9-2*5/3+7/3*99/4*2998+10*568/14))-(-4*3)/(16-3*2))\'
# calcultor(s)



def main():
    print(\'欢迎使用计算器\'.center(60, \'#\'))
    while True:
        formula = input(\'计算式>>:\').strip()
        if formula == \'q\':
            exit()
        elif len(formula) == 0:
            continue
        else:
            formula=check(formula)
            if formula == 1:
                continue
            else:
                result = calcultor(formula)
                print(\'计算结果为：\033[1;31;1m %s\033[0m\' % (result))
                try:
                    print(\'正确答案是：\033[1;31;1m %s\033[0m\' %(eval(formula)))
                except:
                    print(\'无法计算\')



if __name__ == \'__main__\':
    main()