November 2025
Intermediate to advanced
984 pages
16h 17m
Japanese
Content preview from Fluent Python 第2版 ―Pythonicな思考とコーディング手法
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4章Unicode文字列とバイト列
人間は文字を使い、コンピュータはバイト列で会話します。
—— Esther Nam、Travis Fischer
『Character Encoding and Unicode in Python』†1
[†1] PyCon 2014での講演『Character Encoding and Unicode in Python』（https://fpy.li/4-1）の12ページより。動画（https://fpy.li/4-2）も公開されています。
Python 3から、人間が読む文字列と生のバイトによるシーケンスとが明確に区別されるようになりました。暗黙のうちにバイト列がUnicode文字列に変換されるようなことは、もうなくなりました。この章ではUnicode文字列とバイナリシーケンスを扱い、両者間の変換に使われるエンコード形式について解説します。
読者がPythonで行う作業の種類によっては、Unicodeへの理解はさほど必要ないと思われることもあるかもしれません。しかしいずれにせよ、strとbytesの違いを無視することはできません。両者の違いを学んでゆくと、特化したバイナリシーケンスにはPython 2の言わば汎用的なstr型にはない機能が含まれていることもわかるでしょう。
この章で扱うトピックは以下の通りです。
- 文字、コードポイント、バイト表現
- バイナリシーケンス（
bytes、bytearray、memoryview）に固有の機能 - Unicodeの全域と従来の文字セットのためのエンコード形式
- エンコードのエラーへの対応と回避策
- テキストファイルを扱う際のベストプラクティス
- デフォルトのエンコード形式や標準入出力でのありがちな問題
- 正規化済みのUnicode文字列を使った安全な比較 ...
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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.