实现简单的计算器

计算器开发需求

1. 实现加减乘除及拓号优先级解析
2. 用户输入 1 - 2 * ( (60-30 +(-40/5) * (9-2*5/3 + 7 /3*99/4*2998 +10 * 568/14 )) - (-4*3)/ (16-3*2) )等类似公式后，必须自己解析里面的(),+,-,*,/符号和公式，运算后得出结果，结果必须与真实的计算器所得出的结果一致

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105

import re import functools     def minus_operator_handler(formula):     ‘‘‘处理一些特殊的减号运算‘‘‘     minus_operators = re.split("-",formula)     calc_list= re.findall("[0-9]",formula)     if minus_operators[0] == ‘‘: #第一值肯定是负号         calc_list[0] = ‘-%s‘ % calc_list[0]     res = functools.reduce(lambda x,y:float(x) - float(y), calc_list)     print("\033[33;1m减号[%s]处理结果:\033[0m" % formula, res )     return res   def remove_duplicates(formula):     formula = formula.replace("++","+")     formula = formula.replace("+-","-")     formula = formula.replace("-+","-")     formula = formula.replace("--","+")     formula = formula.replace("- -","+")     return formula def compute_mutiply_and_dividend(formula):     ‘‘‘算乘除,传进来的是字符串噢‘‘‘     operators = re.findall("[*/]", formula )     calc_list = re.split("[*/]", formula )     res = None     for index,i in enumerate(calc_list):         if res:             if operators[index-1] == "*":                 res *= float(i)             elif operators[index-1] == "/":                 res /= float(i)         else:             res = float(i)       print("\033[31;1m[%s]运算结果=\033[0m" %formula, res  )     return res def handle_minus_in_list(operator_list,calc_list):     ‘‘‘有的时候把算术符和值分开后,会出现这种情况  [‘-‘, ‘-‘, ‘-‘] [‘ ‘, ‘14969037.996825399 ‘, ‘ ‘, ‘12.0/ 10.0 ‘]        这需要把第2个列表中的空格都变成负号并与其后面的值拼起来,恶心死了     ‘‘‘     for index,i in enumerate(calc_list):         if i == ‘‘: #它其实是代表负号,改成负号             calc_list[index+1] = i + calc_list[index+1].strip() def handle_special_occactions(plus_and_minus_operators,multiply_and_dividend):     ‘‘‘有时会出现这种情况 , [‘-‘, ‘-‘] [‘1 ‘, ‘ 2 * ‘, ‘14969036.7968254‘],2*...后面这段实际是 2*-14969036.7968254,需要特别处理下,太恶心了‘‘‘     for index,i in enumerate(multiply_and_dividend):         i = i.strip()         if i.endswith("*") or i.endswith("/"):             multiply_and_dividend[index] = multiply_and_dividend[index] + plus_and_minus_operators[index] + multiply_and_dividend[index+1]             del multiply_and_dividend[index+1]             del plus_and_minus_operators[index]     return plus_and_minus_operators,multiply_and_dividend def compute(formula):     ‘‘‘这里计算是的不带括号的公式‘‘‘       formula = formula.strip("()") #去除外面包的拓号     formula = remove_duplicates(formula) #去除外重复的+-号     plus_and_minus_operators = re.findall("[+-]", formula)     multiply_and_dividend = re.split("[+-]", formula) #取出乘除公式     if len(multiply_and_dividend[0].strip()) == 0:#代表这肯定是个减号         multiply_and_dividend[1] = plus_and_minus_operators[0] + multiply_and_dividend[1]         del multiply_and_dividend[0]         del plus_and_minus_operators[0]       plus_and_minus_operators,multiply_and_dividend=handle_special_occactions(plus_and_minus_operators,multiply_and_dividend)     for index,i in enumerate(multiply_and_dividend):         if re.search("[*/]" ,i):             sub_res = compute_mutiply_and_dividend(i)             multiply_and_dividend[index] = sub_res       #开始运算+,-     print(multiply_and_dividend, plus_and_minus_operators)     total_res = None     for index,item in enumerate(multiply_and_dividend):         if total_res: #代表不是第一次循环             if plus_and_minus_operators[index-1] == ‘+‘:                 total_res += float(item)             elif plus_and_minus_operators[index-1] == ‘-‘:                 total_res -= float(item)         else:             total_res = float(item)     print("\033[32;1m[%s]运算结果:\033[0m" %formula,total_res)     return total_res   def calc(formula):     ‘‘‘计算程序主入口, 主要逻辑是先计算拓号里的值,算出来后再算乘除,再算加减‘‘‘     parenthesise_flag = True     calc_res = None #初始化运算结果为None,还没开始运算呢,当然为None啦     while parenthesise_flag:         m = re.search("\([^()]*\)", formula) #找到最里层的拓号         if m:             #print("先算拓号里的值:",m.group())             sub_res = compute(m.group())             formula = formula.replace(m.group(),str(sub_res))         else:             print(‘\033[41;1m----没拓号了...---\033[0m‘)               print(‘\n\n\033[42;1m最终结果:\033[0m‘,compute(formula))             parenthesise_flag = False #代表公式里的拓号已经都被剥除啦   if __name__ == ‘__main__‘:       #res = calc("1 - 2 * ( (60-30 +(-40/5) * (9-2*5/3 + 7 /3*99/4*2998 +10 * 568/14 )) - (-4*3)/ (16-3*2) )")     res = calc("1 - 2 * ( (60-30 +(-9-2-5-2*3-5/3-40*4/2-3/5+6*3) * (-9-2-5-2*5/3 + 7 /3*99/4*2998 +10 * 568/14 )) - (-4*3)/ (16-3*2) )")