Calculator function implemented in Python

This article mainly introduces the calculator function implemented by Python, involving the implementation skills of Python's four arithmetic operations, negation, percentage and other related mathematical operation operations. Friends in need can refer to the following

The examples of this article describe Python Implemented calculator function. Share it with everyone for your reference, the details are as follows:

Source code:

# -*- coding:utf-8 -*-
#! python2
from tkinter import *
__author__ = 'tianshl'
__date__ = '2017/10/16'
class Application(Frame):
 def __init__(self):
  Frame.__init__(self)
  self.grid()
  self.mem = ''    # 内存中的数据
  self.opt = ''    # 操作符
  self.display = StringVar() # 显示的数据
  self.display.set('0')  # 初始值
  self.need_cls = False  # 是否需要清屏
  self.create_widgets()
 # 清空
 def clear(self):
  self.mem = ''
  self.display.set('0')
 # 取反
 def negative(self):
  self.display.set(eval('-' + self.display.get()))
 # 四则运算
 def option(self, opt):
  if not self.need_cls:
   self.calculate()
  self.opt = opt
  self.need_cls = True
  self.mem = self.display.get()
 # 计算结果
 def calculate(self):
  if self.opt:
   try:
    self.display.set(eval(self.mem + self.opt + self.display.get()))
   except Exception:
    self.display.set('错误')
    self.need_cls = True
   self.opt = ''
   self.mem = ''
 # 百分比
 def percent(self):
  base = float(self.mem or 1) / 100
  display = eval('{}*{}'.format(self.display.get(), base))
  int_display = int(display)
  display = int_display if display == int_display else display
  self.display.set(display)
  self.need_cls = True
 # 输入
 def input(self, key):
  if self.need_cls:
   self.display.set('0')
   self.need_cls = False
  display = self.display.get()
  if display == '0' and key != '.':
   self.display.set(key)
  else:
   if '.' in display and key == '.':
    return
   self.display.set(display + key)
 # 创建组件
 def create_widgets(self):
  # 显示框
  Entry(self, textvariable=self.display, state="readonly", width=35).grid(
   row=0, column=0, columnspan=4)
  # 键盘
  keyboards = [
   ['C', '+/-', '%', '/'], 
   ['7', '8', '9', '*'], 
   ['4', '5', '6', '-'],
   ['1', '2', '3', '+'],
   ['0', '.', '=']
  ]
  for row, keys in enumerate(keyboards):
   row_num = 3 + row
   for col, key in enumerate(keys):
    if key == 'C':
     command = self.clear
    elif key == '+/-':
     command = self.negative
    elif key == '%':
     command = self.percent
    elif key in ['+', '-', '*', '/']:
     command = lambda s=key: self.option(s)
    elif key == '=':
     command = self.calculate
    else:
     command = lambda s=key: self.input(s)
    bt = Button(self, text=key, command=command, width=6)
    bt.grid(row=row_num, column=col)
app = Application()
# 设置窗口标题:
app.master.title('www.jb51.net - 计算器')
# 设置窗口尺寸/位置
app.master.geometry("326x170+200+200")
# 设置窗口不可变
app.master.resizable(width=False, height=False)
# 主消息循环:
app.mainloop()

Running effect:

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