最简易的python计算器实现源代码

#-*- coding:UTF-8-*-

from Tkinter import *

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

def button(root, side, text, command=None):
    w = Button(root, text=text, command=command)
    w.pack(side=side, expand=YES, fill=BOTH)
    return w
#end of def
#www.iplaypy.com

class Calculator(Frame):
    def __init__(self):
        Frame.__init__(self)
        #self.oprion_add('*Font', 'Verdana 12 bold')
        self.option_add('*Font', 'Verdana 12 bold')
        self.pack(expand=YES, fill=BOTH)
        self.master.title('Simple Cal')
        self.master.iconname('calc1')

        display = StringVar()
        Entry(self, relief=SUNKEN, textvariable=display).pack(side=TOP, expand=YES, fill=BOTH)
        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))
        #end of for
        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))

            #end of if
        #end of for 
        clearF = frame(self, BOTTOM)
        button(clearF, LEFT, 'Clr', lambda w=display: w.set(''))
    #end of def

    def calc(self, display):
        try:
            display.set(eval(display.get()))
        except:
            display.set('ERROR')
        #end of try and except
    #end of def
#end of class

if __name__ == '__main__':
    Calculator().mainloop()