March 2018
Beginner to intermediate
624 pages
16h 10m
Japanese
Content preview from Head First Python 第2版 ―頭とからだで覚えるPythonの基本
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関数呼び出しは失敗することがある
この章の最初の練習問題で特定した最後の問題は、
do_search
関数内の
log_request
の関数呼び
出しに関係します。
4
関数呼び出しが失敗したら？
関数呼び出しが成功する保証はありません。その関数がコードの外側とやり取りする
場合にはなおさらです。
データベースが利用できないと
InterfaceError
を起こしてクラッシュすることは、すでに説明し
ました。
データベースが
ないので、
クラッシュします。
別の問題が発生し、
再びクラッシュしました。
11
章 例外処理
you are here
421
ページをめくる
前に、
raise
の行を
削除して
Web
アプリケーションを
再起動してください。
別の問題も明らかとなります。別のエラーをシミュレートするために、
3
番目の問題の説明で追加し
た
sleep(15)
の行を、
raise
という
1
文に置き換えます。インタプリタが
raise
を実行すると、実
行時エラーが発生します。
Web
アプリケーションを再度試すと、今度は別のエラーが起こります。
何をすべき？
起こりそうな問題を考える
vsearch4web.py
には
4
つの問題が発生する可能性があります。もう一度そ
れぞれよく調べて、対応策を考えましょう。
1.
データベース接続に失敗す
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O’Reilly covers everything we've got, with content to help us build a world-class technology community, upgrade the capabilities and competencies of our teams, and improve overall team performance as well as their engagement.Julian F.
I wanted to learn C and C++, but it didn't click for me until I picked up an O'Reilly book. When I went on the O’Reilly platform, I was astonished to find all the books there, plus live events and sandboxes so you could play around with the technology.Addison B.
I’ve been on the O’Reilly platform for more than eight years. I use a couple of learning platforms, but I'm on O'Reilly more than anybody else. When you're there, you start learning. I'm never disappointed.Amir M.
I'm always learning. So when I got on to O'Reilly, I was like a kid in a candy store. There are playlists. There are answers. There's on-demand training. It's worth its weight in gold, in terms of what it allows me to do.