August 2017
Intermediate to advanced
500 pages
12h 3m
Japanese
Content preview from PythonとJavaScriptではじめるデータビジュアライゼーション
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18
2 章 Python と JavaScript 間の言語学習の橋渡し
from ..io import api #
❸
❶
test_data.py
モジュールをパッケージのトップディレクトリから絶対的にインポート。
❷ 明示的（
. import
）および暗黙的な相対的インポート。
❸
tests
の兄弟パッケージからの相対的インポート。
2.3.4
名前空間の汚染を防ぐ
Python
モジュールで定義した変数はカプセル化されているので、明示的にインポートしている
場合を除き（例えば
from foo import baa
など）、インポートされたモジュールの名前空間から
ドット表記（
foo.baa
など）を使ってアクセスします。このグローバル名前空間のモジュール化は
推奨されていて、暗黙的よりも明示的な文の方が重要であるという
Python
の基本理念
†
の
1
つに
なっています。誰かの
Python
コードを分析する際は、クラス、関数、変数の出所を正確に知るこ
とができるようにします。同じくらい重要なことに、名前空間の保全は変数の衝突やマスキング
（コードベースが大きくなったときの大きな潜在的問題）の可能性を減らします。
JavaScript
に対するもっともな批判としては、「名前空間の規約に関していいかげんである」と
いう指摘があります。最もひどい例は、関数外で宣言した変数や
var
キーワード
‡
のない変数が宣
言されたスクリプト内にとどまらずにグローバルになってしまうことです。この状況を改善する方
法はさまざまありますが、私のお勧めの方法は ...
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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.