Python - Exceptions and Message Boxes: Get the message?(try/except)

Head First Programming
A learner's guide to programming
using the Python language
( O'Reilly Media)
David Griffiths (著) Paul Barry (著)

開発環境

• OS X Mavericks - Apple(OS)
• Emacs (CUI)、BBEdit - Bare Bones Software, Inc. (GUI) (Text Editor)
• Python (プログラミング言語)

Head First Programming A learner's guide to programming using the Python language (David Griffiths(著)、Paul Barry(著)、 O'Reilly Media )のChapter 9(Exceptions and Message Boxes: Get the message?)、EXCEPTION MAGNETS(p.299)を解いてみる。

EXCEPTION MAGNETS(p.299)

コード(BBEdit)

sample299.py

#!/usr/bin/env python3
#-*- coding: utf-8

import tkinter

def saveData():
    try:
        file_data = open('deliveries.txt', 'a')
        file_data.write('Depot:\n')
        file_data.write('{0}\n'.format(depot.get()))
        file_data.write('Description:\n')
        file_data.write('{0}\n'.format(description.get()))
        file_data.write('Address:\n')
        file_data.write('{0}\n'.format(address.get('1.0', tkinter.END)))
        depot.set(None)
        description.delete(0, tkinter.END)
        address.delete('1.0', tkinter.END)
    except Exception as ex:
        app.title("Can't write to the file {0}".format(ex))
        
def readDepots(file):
    with open(file) as f:
        depots = [depot.rstrip() for depot in f]
    return depots

app = tkinter.Tk()
app.title('Head-Ex Delivers')

tkinter.Label(app, text='Deposit:').pack()
depot = tkinter.StringVar()
depot.set(None)
tkinter.OptionMenu(app, depot, *readDepots('depots.txt')).pack()

tkinter.Label(app, text='Description:').pack()
description = tkinter.Entry(app)
description.pack()

tkinter.Label(app, text='Address:').pack()
address = tkinter.Text(app)
address.pack()
tkinter.Button(app, text='Save', command=saveData).pack()

app.mainloop()

GUI

起動時。

例外発生。

入出力結果(Terminal)

$ ls -l deliveries.txt
-rw-r--r--  1 kamimura  staff  149 Jun  2 13:38 deliveries.txt
$ chmod u-w deliveries.txt
$ ls -l deliveries.txt
-r--r--r--  1 kamimura  staff  149 Jun  2 13:38 deliveries.txt
$ ./sample299.py
$