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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4
集合：重複のないオブジェクトの順序なしコレクション
Python
では、集合は一連の関連するオブジェクトを重複することなく格納するための便利な
データ構造です。
さらに、集合に対して和集合、積集合、差集合を求められるというメリットがあります（特に集
合論が好きな人の場合）。
リストや辞書と同様に、集合は必要に応じて拡張（および縮小）できます。集合は、辞書と同様
に順序なしなので、集合内のオブジェクトの順序を推測することはできません。タプルや辞書
と同様に、集合の動作は次の章で説明します。
重複を防ぐデータ構造：集合
最後の組み込みデータ構造は集合です。他のコレクションから素早く重複を取り除きたい
ときに役立ちます。集合という用語が高校の数学の授業を思い出させ、急に冷や汗が出てきた
かもしれませんが、心配いりません。
Python
の集合は多くの状況で利用できます。
集合は一意のオブジェクトの
順序なしコレクションと
考え
ます。重複は
できません。
集合
は
オブジェクト
の
重複
が
できない
。
80/20
のデータ構造経験則
この
4
つの組み込みデータ構造は便利です。これだけでは必要となるデータをすべてカバー
することはできませんが、大部分はカバーできます。これは、汎用性を目的とした技術では普
通のことです。必要なことの約
80%
をカバーし、残りの特殊な
20%
についてはさらに作業が
必要となります。この本では、特殊なデータ要件をサポートできるように
Python
を拡張する
方法を後の章で学ぶのですが、とりあえずこの
2
章と次の
3
章では、 ...
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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.
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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.