python GUI模拟实现计算器

python编写计算器，供大家参考，具体内容如下

（1）计算器界面如下：

（2）基本满足了计算器的所有需求，使用时不可键盘输入，只能鼠标点击左键才可执行。初始时显示0.0，每次输入的内容存于D:\num.txt(启动程序时自动创建)

（3）" AC " 记录清零返回初始 0.0；" delete " 删除上一个输入内容；" +/- " 将正数为负数，负数为正数

（4）对于不同的进制数值系统，小数的精准值不同。
因此计算机会出现 0.1+0.2=0.3000000000004 的现象
能对数据进行截断处理，可以解决问题，但精度丧失。
（此计算机没有进行截断处理）

import tkinter,os
from tkinter import *

def temp(string):#空白间隔
  temp=tkinter.Frame(string,width=20,height=50)
  temp.pack()

flag=0
node=0
def num_work():   #更新显示框Lable
  global flag
  global node
  with open("D:\\num.txt") as f:
    for length in f:
      string=length
  top_work.configure(text=string.strip('\n'))  # 重新设置标签文本
  root.after(500,num_work) # 每隔0.5s调用函数num_work自身获取结果

def num_math_int(num1,num2):#整数运算
  try:
    if num2[0]=='+':
      string=int(num1)+int(num2[1:])
    elif num2[0]=='-':
      string=int(num1)-int(num2[1:])
    elif num2[0]=='x':
      string=int(num1)*int(num2[1:])
    elif num2[0]=='/':
      string=int(num1)/int(num2[1:])

    with open("D:\\num.txt",'a') as f:
      f.write('\n'+str(string)+'\n')
  except:
    with open("D:\\num.txt",'a') as f:
        f.write('\n错误')
def num_math_float(num1,num2):#小数运算
  try:
    if num2[0]=='+':
      string=float(num1)+float(num2[1:])
    elif num2[0]=='-':
      string=float(num1)-float(num2[1:])
    elif num2[0]=='x':
      string=float(num1)*float(num2[1:])
    elif num2[0]=='/':
      string=float(num1)/float(num2[1:])
    if flag==0:
      with open("D:\\num.txt",'a') as f:
        f.write('\n'+str(string)+'\n')
    else:
      with open("D:\\num.txt",'a') as f:
        f.write('\n'+str(string))
  except:
    with open("D:\\num.txt",'a') as f:
        f.write('\n错误')
def decimal(num):
  if num.count('%')>0:
    num=num.replace('%','')
    num=num.replace('\n','')
    if num.isnumeric():
      num=str(float(num)/100)
    else:
      num=num[0]+str(float(num[1:])/100)
  return num

def work(string):#按键对应的功能
  if string.isnumeric():
    with open("D:\\num.txt","a") as file:
      file.write(string)
  else:
    #读取文件D:\\num.txt所有内容
    lists=[]
    with open("D:\\num.txt","r") as file:
      for length in file:
        lists.append(length)

    if string=='AC':
      with open("D:\\num.txt","w") as file:
        file.write('0.0\n')

    elif string=='=':
      num1=lists[-2]
      num2=lists[-1]
      if num1=='\n':#解决末尾为换行的情况
        num1=lists[-3]

      #将百分数小数化
      #出现结果多0.0000000001
      num1=decimal(num1)
      num2=decimal(num2)

      try:      #判断两个数是整数还是小数
        number=int(num1)
        number=int(num2[1:])
        num_math_int(num1,num2)#两个数进行整数运算
      except:
        num_math_float(num1,num2)#两个数进行小数运算

    elif string=='.':
      if lists[-1].count('.')==0:#判断结尾是否有小数点，没有写入否则报错
        with open("D:\\num.txt","a") as file:
          file.write(string)
      else:
        with open("D:\\num.txt","a") as file:
          file.write('\n错误')

    elif string=='+/-':
      if lists[-1].count('-')==0:#-+为-
        if lists[-1].count('+')==1:
          lists[-1]=lists[-1].replace('+','')
        lists[-1]='-'+lists[-1]
      else:           #--为+
        lists[-1]=lists[-1].replace('-','+')
      #更新文件
      with open("D:\\num.txt","w") as file:
        pass
      for length in lists:
        with open("D:\\num.txt","a") as file:
          file.write(length)

    elif string=='delete':
      number=lists[-1]
      lists[-1]=number[0:(len(number)-1)]#删除一位
      #更新文件
      with open("D:\\num.txt","w") as file:
        pass
      for length in lists:
        with open("D:\\num.txt","a") as file:
          file.write(length)
    elif string=='%':
      if lists[-1].endswith("%")==False:
        with open("D:\\num.txt","a") as file:
          file.write(string)
      else:
        with open("D:\\num.txt","a") as file:
          file.write('\n错误')

    else:
      with open("D:\\num.txt","a") as file:
        file.write('\n'+string)

def run():#计算器显示界面主体

  if os.path.exists("D:\\num.txt")==False:
    with open("D:\\num.txt",'w') as f:
      f.write('0.0\n')

  global root#定义全局变量root,方便Label更新
  root=tkinter.Tk()
  root.title("计算器")

  #x = root.winfo_screenwidth()
  #获取当前屏幕的宽
  #y = root.winfo_screenheight()
  #获取当前屏幕的高
  #print(((x-500)//2),((y-600)//2))#为居中提供的参数

  root.geometry('400x500+760+290')#主体长400，高500，居中
  top=tkinter.Frame(root,width=20,height=50)
  top.pack()

  global top_work#定义全局变量root
  temp(top)#空白间隔
  #计算器显示框
  top_work=tkinter.Label(top,text='',justify='left',relief=SUNKEN,bd=10,bg='white',width=40)
  top_work.pack(side='bottom')#计算器显示框（位置居下）
  num_work()
  temp(root)#空白间隔

  number=tkinter.Frame(root)#成放计算机键盘的容器
  number.pack()
  #所有按键，AC键为事例
  numberAC=tkinter.Button(number,text="AC",width=10,command=lambda : work('AC')).grid(row=0,column=0)
  #左键点击，执行函数work
  #按键位置（0,0）

  numberdelete=tkinter.Button(number,text="delete",width=10,command=lambda : work('delete')).grid(row=0,column=1)
  numberzhengfu=tkinter.Button(number,text="+/-",width=10,command=lambda : work('+/-')).grid(row=0,column=2)
  numberchu=tkinter.Button(number,text="/",width=10,command=lambda : work('/')).grid(row=0,column=3)

  tkinter.Button(number,text="7",width=10,command=lambda : work('7')).grid(row=1,column=0)
  tkinter.Button(number,text="8",width=10,command=lambda : work('8')).grid(row=1,column=1)
  tkinter.Button(number,text="9",width=10,command=lambda : work('9')).grid(row=1,column=2)
  tkinter.Button(number,text="x",width=10,command=lambda : work('x')).grid(row=1,column=3)

  tkinter.Button(number,text="4",width=10,command=lambda : work('4')).grid(row=2,column=0)
  tkinter.Button(number,text="5",width=10,command=lambda : work('5')).grid(row=2,column=1)
  tkinter.Button(number,text="6",width=10,command=lambda : work('6')).grid(row=2,column=2)
  tkinter.Button(number,text="-",width=10,command=lambda : work('-')).grid(row=2,column=3)

  tkinter.Button(number,text="1",width=10,command=lambda : work('1')).grid(row=3,column=0)
  tkinter.Button(number,text="2",width=10,command=lambda : work('2')).grid(row=3,column=1)
  tkinter.Button(number,text="3",width=10,command=lambda : work('3')).grid(row=3,column=2)
  tkinter.Button(number,text="+",width=10,command=lambda : work('+')).grid(row=3,column=3)

  tkinter.Button(number,text="%",width=10,command=lambda : work('%')).grid(row=4,column=0)
  tkinter.Button(number,text="0",width=10,command=lambda : work('0')).grid(row=4,column=1)
  tkinter.Button(number,text=".",width=10,command=lambda : work('.')).grid(row=4,column=2)
  tkinter.Button(number,text="=",width=10,command=lambda : work('=')).grid(row=4,column=3)

  root.mainloop()
if __name__=='__main__':
  run()

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