Easter Eggs in Python

役に立たなそうな隠しコマンド的なやつたち。

Hello World

>>> import __hello__
Hello world!

The Zen of Python

>>> import this
The Zen of Python, by Tim Peters

Beautiful is better than ugly.
Explicit is better than implicit.
Simple is better than complex.
Complex is better than complicated.
Flat is better than nested.
Sparse is better than dense.
Readability counts.
Special cases aren't special enough to break the rules.
Although practicality beats purity.
Errors should never pass silently.
Unless explicitly silenced.
In the face of ambiguity, refuse the temptation to guess.
There should be one-- and preferably only one --obvious way to do it.
Although that way may not be obvious at first unless you're Dutch.
Now is better than never.
Although never is often better than right now.
If the implementation is hard to explain, it's a bad idea.
If the implementation is easy to explain, it may be a good idea.
Namespaces are one honking great idea -- let's do more of those!

Antigravity

>>> import antigravity     

Braces is Not a chance…

>>> from __future__ import braces
File "<stdin>", line 1
SyntaxError: not a chance

PDFの日付フォーマットのパース

PDFのメタ情報として格納されている更新日時はModDateとして保存されているが、日付のフォーマットがD:20040401033456-05’00’のような感じでちょっと変わっている。

今回はJavaでこの形式をパースする方法を考える。考えると言っても、PDFBoxに含まれるDateConverter#toCalendar(String)を利用するだけで良い。

final Calendar cal = DateConverter.toCalendar("D:20040401033456-05'00'");

という感じで、Calendarオブジェクトが取得できる。