python 计算器

--coding:utf-8--

from Tkinter import *

创建横条型框架

def frame(root, side):
w = Frame(root)
w.pack(side = side, expand = YES, fill = BOTH)
return w

创建按钮

def button(root, side, text, command = None):
w = Button(root, text = text, command = command)
w.pack(side = side, expand = YES, fill = BOTH)
return w

继承了Frame类，初始化程序界面的布局

class Calculator(Frame):
def init(self):

    Frame.__init__(self)self.pack(expand = YES, fill = BOTH)self.master.title('Simple Calculater')display = StringVar()#添加输入框Entry(self, relief = SUNKEN,textvariable = display).pack(side = TOP, expand = YES,fill = BOTH)#添加横条型框架以及里面的按钮for key in('123', '456', '789', '-0.'):keyF = frame(self, TOP)for char in key:button(keyF, LEFT, char, lambda w = display, c = char:w.set(w.get() + c))#添加操作符按钮opsF = frame(self, TOP)for char in '+-*/=':if char == '=':btn = button(opsF, LEFT, char)btn.bind('<ButtonRelease - 1>', lambda e, s = self, w = display:s.calc(w), '+')else:btn = button(opsF, LEFT, char, lambda w = display, s = '%s' %char:w.set(w.get() + s))#添加清除按钮clearF = frame(self, BOTTOM)button(clearF, LEFT, 'clear', lambda w = display:w.set(''))#调用eval函数计算表达式的值
def calc(self, display):try:display.set(eval(display.get()))except:display.set("ERROR")

程序的入口

if name == 'main':
print('ok')
Calculator().mainloop()