作业：计算器开发

实现加减乘除及拓号优先级解析
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
一、说明：

有一点bug就是不能计算幂次方,如:\’6＊＊6\’会报错

该计算器思路：
1、没用使用递归，先找出并计算所有括号里的公式，再计算乘除和加减
2、所有的数字都认为是浮点型操作，以此来保留小数
使用技术：
1、正则表达式
2、tkinter

二、流程图：

 三、代码如下：

#!/usr/bin/env python3
#antuor:Alan
 
import re
from functools import reduce
from tkinter import *
 
 
 
\'\'\'处理特殊－号运算\'\'\'
def minus_operation(expresstion):
  minus_operators = re.split(\"-\",expresstion)
  calc_list = re.findall(\"[0-9]\",expresstion)
  if minus_operators[0] ==\"\":
    calc_list[0] = \'-%s\' % calc_list[0]
  res = reduce(lambda x,y:float(x)-float(y),calc_list)
  print(\">>>>>>>>>>>>>>减号[%s]运算结果:\" % expresstion,res)
  return res
 
\'\'\'reduce()对sequence连续使用function, 如果不给出initial, 则第一次调用传递sequence的两个元素,
以后把前一次调用的结果和sequence的下一个元素传递给function\'\'\'
 
 
 
 
\'\'\'处理双运算符号\'\'\'
def del_duplicates(expresstion):
  expresstion = expresstion.replace(\"++\",\"+\")
  expresstion = expresstion.replace(\"--\",\"-\")
  expresstion = expresstion.replace(\"+-\",\"-\")
  expresstion = expresstion.replace(\"--\",\"+\")
  expresstion = expresstion.replace(\'- -\',\"+\")
  e
  return expresstion
 
\'\'\'＊／运算函数\'\'\'
def mutiply_dividend(expresstion):
  calc_list = re.split(\"[*/]\",expresstion)     #用＊ or /分割公式
  operators = re.findall(\"[*/]\",expresstion)    #找出所有＊和／号
  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)
  procession0 = \"[%s]运算结果=\" % expresstion,res
  final_result.insert(END,procession0)    #插入窗体
  print(procession0)
  return res
 
 
 
\'\'\'处理运算符号顺序混乱情况\'\'\'
def special_features(plus_and_minus_operators,multiply_and_dividend):
 
  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 minus_special(operator_list,calc_list):
  for index,i in enumerate(calc_list):
    if i ==\'\':
      calc_list[index+1] = i + calc_list[index+1].strip()
 
 
 
\'\'\'运算除了（）的公式＋－＊／\'\'\'
def figure_up(expresstion):
  expresstion = expresstion.strip(\"()\")    #去掉外面括号
  expresstion = del_duplicates(expresstion)  #去掉重复＋－号
  plus_and_minus_operators = re.findall(\"[+-]\",expresstion)
  multiply_and_dividend = re.split(\"[+-]\",expresstion)
  if len(multiply_and_dividend[0].strip()) ==0:
    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 = special_features(plus_and_minus_operators,multiply_and_dividend)
  for index,i in enumerate(multiply_and_dividend):
    if re.search(\"[*/]\",i):
      sub_res = mutiply_dividend(i)
      multiply_and_dividend[index] = sub_res
 
  print(multiply_and_dividend,plus_and_minus_operators)  #计算
  final_res = None
  for index,item in enumerate(multiply_and_dividend):
    if final_res:
      if plus_and_minus_operators[index-1] == \'+\':
        final_res += float(item)
      elif plus_and_minus_operators[index-1] == \'-\':
        final_res -= float(item)
    else:
      final_res = float(item)
  procession = \'[%s]计算结果:\' % expresstion,final_res
  final_result.insert(END,procession)    #插入窗体
  print(procession)
  return final_res
 
\"\"\"主函数：运算逻辑：先计算拓号里的值,算出来后再算乘除,再算加减\"\"\"
def calculate():
  expresstion = expresstions.get()         #获取输入框值
  flage = True
  calculate_res = None               #初始化计算结果为None
  while flage:
    m = re.search(\"\\([^()]*\\)\",expresstion)    #先找最里层的（）
    # pattern = re.compile(r\"\\([^()]*\\)\")
    # m = pattern.match(expresstion)
    if m:
      sub_res = figure_up(m.group())      #运算（）里的公式
      expresstion = expresstion.replace(m.group(),str(sub_res))  #运算完毕把结果替换掉公式
    else:
      print(\'---------------括号已经计算完毕--------------\')
      procession1 = \"最终计算结果:\",figure_up(expresstion)
      final_result.insert(END,procession1)   #插入窗体
      print(\'\\033[31m最终计算结果:\',figure_up(expresstion))
 
      flage = False
 
 
if __name__==\"__main__\":
  # res = calculate(\"1 - 2 * ( (60-30 +(-40/5) * (9-2*5/3 + 7 /3*99/4*2998 +10 * 568/14 )) - (-4*3)/ (16-3*2) )\")
  window = Tk()         ###创建窗体
  window.title(\'计算器\')    ###命名窗体
  frame1 = Frame(window)    ###框架1
  frame1.pack()        ###放置
  frame2 = Frame(window)    ###框架2
  frame2.pack()        ###放置
  lable = Label(frame1,text = \"请输入公式：\")  ###文字标签
  lable.pack()
  expresstions = StringVar()  ###输入框属性，字符串
  entryname = Entry(frame1,textvariable = expresstions) ###文本输入框
  bt_get_expresstions = Button(frame1,text = \"提交\",command = calculate) ###按钮挂件
  bt_get_expresstions.pack()
  entryname.pack()
  lable.grid(row =1,column =1)  ###位置
  entryname.grid(row=1,column =2)
  bt_get_expresstions.grid(row =1,column =3)
  final_result = Text(frame2)  ###计算结果显示框
  final_result.tag_config(\"here\", background=\"yellow\", foreground=\"blue\")
  final_result.pack()
  window.mainloop()       ###事件循环

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