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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152
6 章 Scrapy を使った重量スクレイピング
6.6
リクエストの連結とデータの作成
この節では、
Scrapy
リクエストをつなげ、ハイパーリンクをたどってデータをスクレイピング
できるようにしていきます。まず、
Scrapy
のページキャッシュを有効にしましょう。
xpath
対象
で試すときには、
Wikipedia
の呼び出し数を制限する必要があり、取得したページを格納するのが
エチケットです。世の中にある一部のデータセットとは異なり、ノーベル賞受賞者のデータセット
は変更がありますが、
1
年に一度です
†
。
6.6.1
ページのキャッシュ
ご推察のとおり、
Scrapy
はページキャッシュをきめ細かく制御できる高度なキャッシュシステ
ム（
http://bit.ly/1UAqGVp
）を備えています（例えば、ストレージバックエンドをデータベース
にするかファイルシステムにするかやページの有効期限などを選ぶことができます）。このキャッ
シュシステムは、プロジェクトの
settings.py
モジュールで有効にできるミドルウェア（
http://
bit.ly/261CIhH
）として実装されています。さまざまなオプションを利用できますが、ノーベル賞
スクレイピングのためには、
HTTPCACHE_ENABLED
を
True
に設定するだけで十分です。
# -*- coding: utf-8 -*-
# nobel_winners project
のための
Scrapy
設定
#
#
このファイルにはデフォルトで最も重要な設定だけが含まれる。 ...
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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.