Python-сообщество

#!/usr/bin/env python
#-*- coding: utf8 -*-
from Tkinter import *
from tkFileDialog import *
from random import randint


class App(object):
    def __init__(self):
        self.key = [3, 1, 4, 1, 5]
        self.root = Tk()
        self.btn_open = Button(self.root, command=self.open_file, text = 'Open')
        self.btn_open.pack()
        self.txt = Text(self.root)
        self.txt.pack()
        self.btn_enc = Button(self.root, command=self.encode, text = 'Encode')
        self.btn_enc.pack()
        self.btn_dec = Button(self.root, command=self.decode, text = 'Decode')
        self.btn_dec.pack()

    def open_file(self):
        self.txt.delete('1.0',END)
        self.txt.insert(INSERT, askopenfile().read())

    def encode(self):
            indata=self.txt.get('1.0',END)
            outdata = ''
            if len(indata)>0 and indata[-1]=='\n':
                indata = indata[:-1]

            i = 0
            for sym in indata:
                if sym>='A' and sym<='Z':
                    outdata+=chr(((ord(sym)-ord('A'))+self.key[i])%(ord('Z')-ord('A')+1)+ord('A'))
                elif sym>='a' and sym<='z':
                    outdata+=chr(((ord(sym)-ord('a'))+self.key[i])%(ord('z')-ord('a')+1)+ord('a'))
                else:
                    outdata += sym
                i += 1
                if i == len(self.key):
                    i = 0
                self.txt.delete('1.0',END)
                self.txt.insert(INSERT, outdata)

    def decode(self):
            indata=self.txt.get('1.0',END)
            outdata = ''
            if len(indata)>0 and indata[-1]=='\n':
                indata = indata[:-1]

            i = 0
            for sym in indata:
                if sym>='A' and sym<='Z':
                    outdata+=chr(((ord(sym)-ord('A'))-self.key[i])%(ord('Z')-ord('A')+1)+ord('A'))
                elif sym>='a' and sym<='z':
                    outdata+=chr(((ord(sym)-ord('a'))-self.key[i])%(ord('z')-ord('a')+1)+ord('a'))
                else:
                    outdata += sym
                i += 1
                if i == len(self.key):
                    i = 0
                self.txt.delete('1.0',END)
                self.txt.insert(INSERT, outdata)

    def on_execute(self):
        self.root.mainloop()

if __name__ == '__main__':
    app = App()
    app.on_execute()