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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363
16.8 バインディングされたデータへのアクセス
図
16-16
は、最後の
4
本の棒のために生成された
HTML
を表しています。いずれわかるよう
に、最初の
2
つの要素のデータは初めの棒グループに追加した
2
つのダミーノードにバインディ
ングされています。これを使った長方形の属性の調整はまだ行っていません。新しいデータを使っ
て以前の棒を更新することは、すぐ後で説明しますが、更新パターンの主要な要素の
1
つです。
■
何度も言いますが、
enter
と
exit
（および
remove
）に真剣に向き合うことは
D3
の健全な上達
に欠かせません。いろいろと使ってみて、作成した
HTML
を調べ、少量のデータを投入し、普通
は多少面倒なことも体験して一部始終を学びます。
D3
の中核である更新パターンに進む前に、バ
インディングされたデータにアクセスする方法を少し調べてみましょう。
16.8
バインディングされたデータへのアクセス
DOM
に何が起こっているかを確認するには、ブラウザの
HTML
インスペクタやコンソール
を使って
D3
の変化を追跡することです。図
16-17
では、データをバインディングする前と
data
メソッドで棒に
nobelData
をバインディングした後の図
16-15
の最初の棒を表す
rect
要素を
Chrome
のコンソールを使って調べています。
D3
は
rect
要素に
_ _data_ _
オブジェクトを追加
し、そのオブジェクトにバインディングしたデータ（この例では
nobelData
リストの最初のメン
バー）を格納します。
D3
の内部管理機能がこの ...
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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.