calc.py

'''
 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
calcStr = "1 - 2 * ( (60-30 +(-40/5) * (9-2*5/3 + 7 /3*99/4*2998 +10 * 568/14 )) - (-4*3)/ (16-3*2) )"
calcStr = re.sub("\ ","",calcStr)   #   清除输入中的空格
sepStr = ""

def multiplyDivideFunc(inStr):
    outList = list()
    if "*" in inStr:
        # print("Multiply in inStr")
        outList = inStr.split("*")
        # print(float(outList[0])*float(outList[1]))
        return float(outList[0])*float(outList[1])
    elif "/" in inStr:
        # print("Divide in inStr")
        outList = inStr.split("/")
        # print(float(outList[0]) / float(outList[1]))
        return float(outList[0]) / float(outList[1])
    else:
        # print("Only a digit:", float(inStr))
        return float(inStr)

def strExecute(inStr):              #查找字符串中的最高优先级算式，并返回字符串
    # print(inStr)
    outStr = ""
    outStr = re.search("\([\(\)\+\-\*/\d]+",inStr)

    if ((outStr is not None) and ("(" in inStr)):
        outStr = strExecute(outStr.group(0)[1:])
        # return outStr
        return re.search("[^\(\)]*",outStr).group(0)
    else:
        # return inStr
        return re.search("[^\(\)]*",inStr).group(0)

def plusMinusDiv(inStr):
    ret = re.split("[\-\+]",inStr)
    if ret[0] == '':
        ret.pop(0)
    ret[0] = '-1' + ret[0]
    return ret

sepStr = strExecute(calcStr)
print("[Final]:",sepStr)

r = plusMinusDiv("-9-2*5/3+7/3*99/4*2998+10*568/14")
print(r)