实现计算器

import re

def clear(Re,res1):
    Re=re.sub(‘[()]‘,‘‘,Re)
    res= re.sub(‘\([^()]+\)‘,Re,res1,1)
    res= re.sub("\+\+|--", "+", res)
    res= re.sub("\+-|-\+", "-", res)
    return res

def muldiv(res):
    while re.search(‘-?\d+\.?\d*[\*\/]-?\d+\.?\d*‘,res):
        Re=re.search(‘-?\d+\.?\d*[\*\/]-?\d+\.?\d*‘,res).group()
        if re.search(‘-?\d+\.?\d*\*-?\d+\.?\d*‘,Re):
            m,n=re.split(‘\*‘,Re)
            total=float(m)*float(n)
            if re.search(‘-\d+\.?\d*\*-\d+\.?\d*‘,res):
                res = re.sub("-?\d+\.?\d*\*-?\d+\.?\d*",("+"+str(total)),res,1)
                return muldiv(res)
            else:
                res=re.sub(‘-?\d+\.?\d*\*-?\d+\.?\d*‘,str(total),res,1)
                return muldiv(res)
        if re.search(‘-?\d+\.?\d*\/-?\d+\.?\d*‘, Re):
            m,n=re.split(‘\/‘,Re)
            total=float(m)/float(n)
            res=re.sub(‘-?\d+\.?\d*\/-?\d+\.?\d*‘,str(total),res,1)
            return muldiv(res)
    return res

def addsub(res):
    while re.search(‘-?\d+\.?\d*[\+\-]-?\d+\.?\d*‘,res):
        Re=re.search(‘-?\d+\.?\d*[\+\-]-?\d+\.?\d*‘,res).group()
        if re.search(‘-?\d+\.?\d*\+-?\d+\.?\d*‘,Re):
            m,n=re.split(‘\+‘,Re)
            total=float(m)+float(n)
            res=re.sub(‘-?\d+\.?\d*\+-?\d+\.?\d*‘,str(total),res,1)
            return  addsub(res)
        if re.search(‘-?\d+\.?\d*\--?\d+\.?\d*‘,Re):
            m, n = re.split(‘\-‘, Re)
            total = float(m) - float(n)
            res = re.sub(‘-?\d+\.?\d*\--?\d+\.?\d*‘, str(total), res, 1)
            return addsub(res)
    return res

def count(res):
    while re.search(‘\([^()]+\)‘,res):
        Re= re.search(‘\([^()]+\)‘,res).group()
        Re1=muldiv(Re)
        Re2=addsub(Re1)
        Clear=clear(Re2, res)
        return count(Clear)
    else:
        Re1 = muldiv(res)
        Re2 = addsub(Re1)
        return Re2
s=input(‘请输入想计算的内容：‘)
s=re.sub(‘ ‘,‘‘,s)
print(count(s))