def mul_div(exp): #计算乘除
while True:
ret = re.search('[\d\.]+[\*\/]-?[\d\.]+', exp)
if ret:
atom_exp = ret.group()
res = atom_cal(atom_exp)
exp = exp.replace(atom_exp, res)
else:
return fomat_exp(exp)
def fomat_exp(exp): #计算乘除后,统一符号
exp=exp.replace('--','+')
exp=exp.replace('-+','-')
exp=exp.replace('++','+')
exp=exp.replace('+-','-')
return add_sub(exp)
def add_sub(exp): #计算加减
ret=re.findall('[\-\+]?[\d\.]+',exp)
exp_sum=0
for i in ret:
exp_sum+=float(i)
return exp_sum
def main(exp): #主程序,先计算括号内的
exp=exp.replace(' ','')
while True:
ret=re.search('\([^()]+\)',exp)
if ret:
inner_bracket=ret.group()
res=str(mul_div(inner_bracket))
exp = exp.replace(inner_bracket, res)
else:break
return mul_div(exp)
exp = '1 - 2 * ( (60-30 +(-40/5) * (9-2*5/3 + 7 /3*99/4*2998 +10 * 568/14 )) - (-4*3)/ (16-3*2) )'
print(main(exp))
