Python实现两款计算器功能示例

#计算一个表达式的时候，首先肯定是先算括号里面的，再算乘除法，后算加减法
import re
# 1.去括号
def remove_kuohao(expression):
  '''
  这是一个去除括号的函数
  :param expression: 传进来的表达式
  :return: 计算后的结果
  '''
  while True:
    ret = re.search(r'\([^(]*"htmlcode">

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('- -', "+")
  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:%s\n"%figure_up(expresstion)
      print(procession1)
      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_slaves(row=1,column=1)
  entryname.grid_slaves(row=1,column=1)
  bt_get_expresstions.grid_slaves(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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