python3简单实现支持括号的加减乘除运算，,1.首先表达式的空格

python3简单实现支持括号的加减乘除运算，,1.首先表达式的空格

1.首先表达式的空格。2.循环计算最内层带括号的表达式（提取运算符出现的顺序，然后计算）3.计算最外层的表达式输出。刚接触python，代码不够严谨，仅实现功能。不知道如何在函数中使用运算符变量做运算（使用的时候是字符串形式），希望知道的朋友告诉我，互相学习一下。

import re,mathdef qcysf(s):    while re.findall(‘\+\-|\+\+|\-\-|\-\+‘,s):        s = s.replace(‘+-‘,‘-‘)        s = s.replace(‘++‘,‘+‘)        s = s.replace(‘--‘,‘+‘)        s = s.replace(‘-+‘,‘-‘)    return sdef yunsuan(a1):    temp1 = re.sub(‘\d|\.|\+|-| ‘,‘‘,a1)    # print(temp1)    # print(a1)    for i in temp1:        if i == "*":            b = re.search(‘(-?\d+\.?\d*\*-?\d+\.?\d*)‘, a1).group()            # print(b)            temp2 = round(float(b.split(‘*‘)[0]) * float(b.split(‘*‘)[1]),10)            temp2 = ‘+‘ + str(temp2)            a1 = a1.replace(b, temp2,1)            # print(a1)        else:            b = re.search(‘(-?\d+\.?\d*/-?\d+\.?\d*)‘, a1).group()            # print(b)            temp2 = round(float(b.split(‘/‘)[0]) / float(b.split(‘/‘)[1]),10)            temp2 = ‘+‘ + str(temp2)            a1 = a1.replace(b, temp2,1)            # print(a1)    a1 = qcysf(a1)    # print(a1)    a2 = a1.lstrip(‘-‘)    temp3 = re.sub(‘\d|\.| ‘, ‘‘, a2)    for i in temp3:        if i == "+":                b = re.search(‘(-?\d+\.?\d*\+\d+\.?\d*)‘, a1).group()                temp2 = round(float(b.split(‘+‘)[0]) + float(b.split(‘+‘)[1]),10)                a1 = a1.replace(b, str(temp2),1)                # print(a1)        else:            b = re.search(‘(\d+\.?\d*\-\d+\.?\d*)‘, a1).group()            temp2 = round(float(b.split(‘-‘)[0]) - float(b.split(‘-‘)[1]),10)            a1 = a1.replace(b, str(temp2),1)            # print(a1)    return a1if __name__ == "__main__":    a = input(‘请输入你要计算的内容：‘)    a = a.replace(‘ ‘,‘‘)    # print(a)    if re.findall(‘[a-zA-Z]]‘,a):        print(‘你输入的内容不合法‘)    else:        while re.search("\([^()]+\)", a):            b = re.search("\([^()]+\)", a).group()            # b = qcysf(b)            # print(a)            # print(b)            b1 = re.sub(‘\(|\)‘,‘‘,b)            # print(a)            temp = yunsuan(b1)            a = a.replace(b, str(temp))        # print(‘这是倒数第二个‘,a)        a = qcysf(a)        a = yunsuan(a)        print(a)

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请输入你要计算的内容：1 - 2 * ( (60-30 +(-40/5) * (9-2*5/3 + 7 /3*99/4*2998 +10 * 568/14 )) - (-4*3)/ (16-3*2) )
2776672.6951997215

python3简单实现支持括号的加减乘除运算