计算器

import re
#乘除运算
def mult_div(args):
    chen_chu = re.compile(r'[\-\+]?(\-?\d+\.?\d*)([\*\/])(\-?\d+\.?\d*)')  #取出 [-]x*[-]y 或 [-]x/[-]y
    while chen_chu.search(args):                         #有符合条件的程序就一直执行，直到匹配不到返回None
        m = chen_chu.findall(args)
        for tup in m:
            num1,symbol,num2 = tup
            if symbol == '*':
                result = float(num1) * float(num2)
            elif symbol == '/':
                result = float(num1) / float(num2)
            args = args.replace(num1+symbol+num2, str(result), 1)
    return args

#加减运算
def plus_minu(args):
    args = args.replace('++', '+')     #将计算过程中出现的不规则运算符替换
    args = args.replace('+-', '-')
    args = args.replace('-+', '-')
    args = args.replace('--', '+')
    jia_jian = re.compile(r'(\-?\d+\.?\d*)([\-\+])(\d+\.?\d*)')    #查找  [-]x +\- y ,并对数字和运算符号分组
    while jia_jian.search(args):
        m = jia_jian.search(args)
        num = m.group()
        num1 = float(m.group(1))
        symbol = m.group(2)
        num3 = float(m.group(3))

        if symbol == '-':
            result = num1 - num3
        elif symbol == '+':
            result = num1 + num3
        args = args.replace(num, str(result), 1)
    return args

#取括号并进行括号内加减运算
def bracket(value):
    kuohao = re.compile(r'\([^()]*\)')         #取括号
    while kuohao.search(value):                #有符合条件的就一直循环，直到返回None时结束
        m = kuohao.search(value)
        res = m.group()
        res_mult = mult_div(res)                #括号内乘除法运算
        res_mult = res_mult.strip('(').strip(')')  #去 两边 （）号
        result = plus_minu(res_mult)              #加减运算
        value = value.replace(res,result,1)  #替换
    return value

if __name__ == "__main__":
    expression = '1-2*((60+2*(-3-40.0/5)*(9-2*5/3+7/3*99/4*2998+10*568/14))-(-4*3)/(16-3*2))'
    result=plus_minu(mult_div(bracket(expression)))
    print('结果：', round(float(result)))