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Python实现的计算器功能

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发布： 2018-04-26 16:39:34

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这篇文章主要介绍了Python实现的计算器功能,涉及Python四则运算、取反、百分比等相关数学运算操作实现技巧,需要的朋友可以参考下

本文实例讲述了Python实现的计算器功能。分享给大家供大家参考，具体如下：

源码：

# -*- coding:utf-8 -*-
#! python2
from tkinter import *
__author__ = &#39;tianshl&#39;
__date__ = &#39;2017/10/16&#39;
class Application(Frame):
 def __init__(self):
  Frame.__init__(self)
  self.grid()
  self.mem = &#39;&#39;    # 内存中的数据
  self.opt = &#39;&#39;    # 操作符
  self.display = StringVar() # 显示的数据
  self.display.set(&#39;0&#39;)  # 初始值
  self.need_cls = False  # 是否需要清屏
  self.create_widgets()
 # 清空
 def clear(self):
  self.mem = &#39;&#39;
  self.display.set(&#39;0&#39;)
 # 取反
 def negative(self):
  self.display.set(eval(&#39;-&#39; + 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(&#39;错误&#39;)
    self.need_cls = True
   self.opt = &#39;&#39;
   self.mem = &#39;&#39;
 # 百分比
 def percent(self):
  base = float(self.mem or 1) / 100
  display = eval(&#39;{}*{}&#39;.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(&#39;0&#39;)
   self.need_cls = False
  display = self.display.get()
  if display == &#39;0&#39; and key != &#39;.&#39;:
   self.display.set(key)
  else:
   if &#39;.&#39; in display and key == &#39;.&#39;:
    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 = [
   [&#39;C&#39;, &#39;+/-&#39;, &#39;%&#39;, &#39;/&#39;], 
   [&#39;7&#39;, &#39;8&#39;, &#39;9&#39;, &#39;*&#39;], 
   [&#39;4&#39;, &#39;5&#39;, &#39;6&#39;, &#39;-&#39;],
   [&#39;1&#39;, &#39;2&#39;, &#39;3&#39;, &#39;+&#39;],
   [&#39;0&#39;, &#39;.&#39;, &#39;=&#39;]
  ]
  for row, keys in enumerate(keyboards):
   row_num = 3 + row
   for col, key in enumerate(keys):
    if key == &#39;C&#39;:
     command = self.clear
    elif key == &#39;+/-&#39;:
     command = self.negative
    elif key == &#39;%&#39;:
     command = self.percent
    elif key in [&#39;+&#39;, &#39;-&#39;, &#39;*&#39;, &#39;/&#39;]:
     command = lambda s=key: self.option(s)
    elif key == &#39;=&#39;:
     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(&#39;www.jb51.net - 计算器&#39;)
# 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()

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运行效果：