简单的计算功能，还需要优化

#还有需要优化的
#!/usr/bin/env python3
Example = '1-2*((60-30+(9-2*5/-3+7/3*99/4*2998+10*568/14)*(-40/5))-(-4*3)/(16-3*2))'
import re
# 乘法函数
def multiplication():
    value = 0
    for n, i in enumerate(new_value):
        if n != 0:
            fa = '%.2f'%(float(new_value[n-1]))
            fb = '%.2f'%(float(new_value[n]))
            value = '%.2f'%(float(fa) * float(fb))
    return value
# 除法函数
def division():
    value = 0
    for n, i in enumerate(new_value):
        if n != 0:
            fa = '%.2f'%(float(new_value[n - 1]))
            fb = '%.2f'%(float(new_value[n]))
            value = '%.2f'%(float(fa) / float(fb))
    return value
# 加法函数
def addition():
    value =0
    for n, i in enumerate(new_value):
        if n != 0:
            fa = '%.2f'%(float(new_value[n - 1]))
            fb = '%.2f'%(float(new_value[n]))
            value = '%.2f'%(float(fa) + float(fb))
    return value
# 减法函数
def subtraction():
    value = 0
    for n, i in enumerate(new_value):
        if n != 0:
            fa = '%.2f'%(float(new_value[n - 1]))
            fb = '%.2f'%(float(new_value[n]))
            value = '%.2f'%(float(fa) - float(fb))
    return value
print(eval(Example))


while True:
    brackets = re.search("\([^()]*\)",Example) #匹配括号内容，'\('中\表示转义，serach函数匹配所有字符串
    if brackets:
        take_off_brackets = brackets.group().strip('()')#脱掉括号
        while True:
            element = re.findall('-?\d+\.\d+|\d+', take_off_brackets)
            if len(element) > 1:  #计算take_off_brackets中的元素数量是否大于1
                print(take_off_brackets)
                if '*' in take_off_brackets or '/' in take_off_brackets: #判断字符串中带有'*'或者'/'
                    multiplication_and_division = re.search('(\d+\.\d+|\d+)(\*|\/)(-?\d+\.\d+|-?\d+)',take_off_brackets)#匹配字符串中的乘法和除法，
                    # 其中'\d+\.\d+'表示匹配浮点，'\d+'表示整数，(\d+\.\d+|\d+)表示匹配浮点或者整数，括号表示这是一组，(\*|\/)表示匹配'*'或者'/'，
                    # (-?\d+\.\d+|-?\d+)中-?\d+\.\d+表示正浮点数或者负浮点数，-?\d+表示正数或者负数
                    if multiplication_and_division:
                        mul_and_div = multiplication_and_division.group()
                        if '*' in mul_and_div:
                            new_value = mul_and_div.split('*') #将mul_and_div以*隔开生成列表
                            replace = multiplication()
                            take_off_brackets = re.sub('(\d+\.\d+|\d+)\*(-?\d+\.\d+|-?\d+)',str(replace),take_off_brackets,1)
                            # print(take_off_brackets)
                            continue
                        elif '/' in mul_and_div:
                            new_value = mul_and_div.split('/')
                            replace = division()
                            take_off_brackets = re.sub('(\d+\.\d+|\d+)\/(-?\d+\.\d+|-?\d+)',str(replace),take_off_brackets,1)
                            # print(take_off_brackets)
                            continue
                        else:
                            break
                    else:
                        break
                elif '+' in take_off_brackets or '-' in take_off_brackets:
                    addition_and_subtraction = re.search('(\d+\.\d+|\d+)(\+|\-)(-?\d+\.\d+|-?\d+)',take_off_brackets)
                    if addition_and_subtraction:
                        add_and_sub = addition_and_subtraction.group()
                        if '+' in add_and_sub:
                            if '++' in add_and_sub:
                                new_value = add_and_sub.split('+', 1)
                                replace = addition()
                                take_off_brackets = re.sub('(\d+\.\d+|\d+)\+(-?\d+\.\d+|-?\d+)', str(replace), take_off_brackets, 1)
                                # print(take_off_brackets)
                                continue
                            else:
                                new_value = add_and_sub.split('+')
                                replace = addition()
                                take_off_brackets = re.sub('(\d+\.\d+|\d+)\+(-?\d+\.\d+|-?\d+)', str(replace), take_off_brackets, 1)
                                # print(take_off_brackets)
                                continue
                        elif '-' in add_and_sub:
                            if '--' in add_and_sub:
                                new_value = add_and_sub.split('-', 1)
                                replace = subtraction()
                                take_off_brackets = re.sub('(\d+\.\d+|\d+)\-(-?\d+\.\d+|-?\d+)', str(replace), take_off_brackets, 1)
                                # print(take_off_brackets)
                                continue
                            else:
                                new_value = add_and_sub.split('-')
                                replace = subtraction()
                                take_off_brackets = re.sub('(\d+\.\d+|\d+)\-(-?\d+\.\d+|-?\d+)', str(replace), take_off_brackets, 1)
                                # print(take_off_brackets)
                                continue
                        else:
                            break
                    else:
                        break
                else:
                    break
            else:
                # take_off_brackets = brackets.group().strip('()')
                aa = re.sub('\+','\+',brackets.group()) #将字符串中的'+'、'-'、'*'、'/'都加上转义符'/'这样替换的时候才能找到
                bb = re.sub('\-','\-',aa)
                cc = re.sub('\*','\*',bb)
                dd = re.sub('\/','\/',cc)
                Example = re.sub(dd, str(take_off_brackets).strip('()'), Example, 1)
                brackets = re.search("\([^()]*\)", Example)
                tt = re.sub('\(','\(',brackets.group())
                yy = re.sub('\)','\)',tt)
                Example = re.sub(yy,take_off_brackets,Example)
                print(Example)
                break
    else:
        while True:
            if '*' in Example or '/' in Example:
                multiplication_and_division = re.search('(\d+\.\d+|\d+)(\*|\/)(-?\d+\.\d+|-?\d+)', Example)
                if multiplication_and_division:
                    mul_and_div = multiplication_and_division.group()
                    if '*' in mul_and_div:
                        new_value = mul_and_div.split('*') #将mul_and_div以*隔开生成列表
                        replace = multiplication()
                        Example = re.sub('(\d+\.\d+|\d+)\*(-?\d+\.\d+|-?\d+)',str(replace),Example,1)
                        print(Example)
                        continue
                    elif '/' in mul_and_div:
                        new_value = mul_and_div.split('/')
                        replace = division()
                        Example = re.sub('(\d+\.\d+|\d+)\/(-?\d+\.\d+|-?\d+)',str(replace),Example,1)
                        print(Example)
                        continue
                    else:
                        break
                else:
                    break
            elif '+' in Example or '-' in Example:
                addition_and_subtraction = re.search('(\d+\.\d+|\d+)(\+|\-)(-?\d+\.\d+|-?\d+)', Example)
                if addition_and_subtraction:
                    add_and_sub = addition_and_subtraction.group()
                    if '+' in add_and_sub:
                        if '++' in add_and_sub:
                            new_value = add_and_sub.split('+', 1)
                            replace = addition()
                            Example = re.sub('(\d+\.\d+|\d+)\+(-?\d+\.\d+|-?\d+)', str(replace), Example, 1)
                            print(Example)
                            continue
                        else:
                            new_value = add_and_sub.split('+')
                            replace = addition()
                            Example = re.sub('(\d+\.\d+|\d+)\+(-?\d+\.\d+|-?\d+)', str(replace), Example, 1)
                            print(Example)
                            continue
                    elif '-' in add_and_sub:
                        if '--' in add_and_sub:
                            new_value = add_and_sub.split('-', 1)
                            replace = subtraction()
                            Example = re.sub('(\d+\.\d+|\d+)\-(-?\d+\.\d+|-?\d+)', str(replace), Example, 1)
                            print(Example)
                            continue
                        else:
                            new_value = add_and_sub.split('-')
                            replace = subtraction()
                            Example = re.sub('(\d+\.\d+|\d+)\-(-?\d+\.\d+|-?\d+)', str(replace), Example, 1)
                            print(Example)
                            continue
                    else:
                        break
                else:
                    break