A simple calculator，simplecalculator,from Tkinter

A simple calculator，simplecalculator,from Tkinter

from Tkinter import *def frame(root, side):     w = Frame(root)    w.pack(side=side, expand=YES, fill=BOTH)    return wdef button(root, side, text, command=None):     w = Button(root, text=text, command=command)     w.pack(side=side, expand=YES, fill=BOTH)    return wclass Calculator(Frame):    def __init__(self):        Frame.__init__(self)        self.option_add('*Font', 'Verdana 12 bold')        self.pack(expand=YES, fill=BOTH)        self.master.title('Simple Calculator')        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))        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))        clearF = frame(self, BOTTOM)        button(clearF, LEFT, 'Clr', lambda w=display: w.set(''))    def calc(self, display):        try:            display.set('eval(display.get())')        except:            display.set('ERROR')if __name__ == '__main__':    Calculator().mainloop()