Python写计算器详解编程语言

    # -*- coding: utf-8 -*-   
    #author: Cullen   
    #import the module   
       
    from Tkinter import *   
    from functools import partial   
    import tkFont   
       
    def get_input(entry, argu):   
        entry.insert(END, argu)   
       
    def backspace(entry):   
        input_len = len(entry.get())   
        entry.delete(input_len - 1)   
       
    def clear(entry):   
        entry.delete(0, END)   
       
    def calc(entry):   
        input = entry.get()   
        output = str(eval(input.strip()))   
        clear(entry)   
        entry.insert(END, output)   
       
    def cal():   
        root = Tk()   
        root.title("Calc")   
        root.resizable(0,0)   
       
        entry_font = tkFont.Font(size=12)   
        entry = Entry(root, justify="right", font=entry_font)   
        entry.grid(row=0, column=0, columnspan=4, sticky=N+W+S+E, padx=5,  pady=5)   
       
        button_font = tkFont.Font(size=10, weight=tkFont.BOLD)   
        button_bg = '#D5E0EE'   
        button_active_bg = '#E5E35B'   
       
        myButton = partial(Button, root, bg=button_bg, padx=10, pady=3, activebackground = button_active_bg)   
       
        button7 = myButton(text='7', command=lambda : get_input(entry, '7'))   
        button7.grid(row=1, column=0, pady=5)   
       
        button8 = myButton(text='8', command=lambda : get_input(entry, '8'))   
        button8.grid(row=1, column=1, pady=5)   
       
        button9 = myButton(text='9', command=lambda : get_input(entry, '9'))   
        button9.grid(row=1, column=2, pady=5)   
       
        button10 = myButton(text='+', command=lambda : get_input(entry, '+'))   
        button10.grid(row=1, column=3, pady=5)   
       
        button4 = myButton(text='4', command=lambda : get_input(entry, '4'))   
        button4.grid(row=2, column=0, pady=5)   
       
        button5 = myButton(text='5', command=lambda : get_input(entry, '5'))   
        button5.grid(row=2, column=1, pady=5)   
       
        button6 = myButton(text='6', command=lambda : get_input(entry, '6'))   
        button6.grid(row=2, column=2, pady=5)   
       
        button11 = myButton(text='-', command=lambda : get_input(entry, '-'))   
        button11.grid(row=2, column=3, pady=5)   
       
        button1 = myButton(text='1', command=lambda : get_input(entry, '1'))   
        button1.grid(row=3, column=0, pady=5)   
       
        button2 = myButton(text='2', command=lambda : get_input(entry, '2'))   
        button2.grid(row=3, column=1, pady=5)   
       
        button3 = myButton(text='3', command=lambda : get_input(entry, '3'))   
        button3.grid(row=3, column=2, pady=5)   
       
        button12 = myButton(text='*', command=lambda : get_input(entry, '*'))   
        button12.grid(row=3, column=3, pady=5)   
       
        button0 = myButton(text='0', command=lambda : get_input(entry, '0'))   
        button0.grid(row=4, column=0, columnspan=2, padx=3, pady=5, sticky=N+S+E+W)   
       
        button13 = myButton(text='.', command=lambda : get_input(entry, '.'))   
        button13.grid(row=4, column=2, pady=5)   
       
        button14 = Button(root, text='/', bg=button_bg, padx=10, pady=3,   
                          command=lambda : get_input(entry, '/'))   
        button14.grid(row=4, column=3, pady=5)   
       
        button15 = Button(root, text='<-', bg=button_bg, padx=10, pady=3,   
                          command=lambda : backspace(entry), activebackground = button_active_bg)   
        button15.grid(row=5, column=0, pady=5)   
       
        button16 = Button(root, text='C', bg=button_bg, padx=10, pady=3,   
                          command=lambda : clear(entry), activebackground = button_active_bg)   
        button16.grid(row=5, column=1, pady=5)   
       
        button17 = Button(root, text='=', bg=button_bg, padx=10, pady=3,   
                          command=lambda : calc(entry), activebackground = button_active_bg)   
        button17.grid(row=5, column=2, columnspan=2, padx=3, pady=5, sticky=N+S+E+W)   
       
        root.mainloop()   
       
    if __name__ == '__main__':   
        cal()