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
Become an O’Reilly member and get unlimited access to this title plus top books and audiobooks from O’Reilly and nearly 200 top publishers, thousands of courses curated by job role, 150+ live events each month,
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.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.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.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.
178
8 章 pandas 入門
8.3
異種データと測定値の分類
次の節では
pandas
の中心的な概念を説明し、
DataFrame
についてと、
CSV
ファイルや
SQL
デー
タベースなどの一般的なデータストアにデータを出し入れする方法を重点的に取り上げます。し
かし、まずは少し寄り道をして、
pandas
の処理対象でありデータ可視化の中心となる異種データ
セットの本当の意味を考えてみましょう。
おそらく、可視化（記事や最近の
Web
ダッシュボードで説明するのに使う棒グラフや折れ線グ
ラフなど）は実際の世界の測定結果を表します。時間とともに変わる物価、
1
年間の降水量の変
化、人種の違いによる投票傾向などです。このような測定値は、大まかに数値とカテゴリの
2
つ
のグループに分けられます。数値は間隔と比率のスケールに分けられ、カテゴリ値は名義と順序に
分けられます。したがって、データ可視化では大まかに
4
つの観測カテゴリが利用できます。
これらの測定カテゴリを示すために、例として一連のツイートを取り上げてみましょう。ツイー
トにはさまざまなデータフィールドがあります。
{
"text": "#Python and #JavaScript sitting in a tree...", #
❶
"id": 2103303030333004303, #
❶
"favorited": true, #
❷
"filter_level":"medium", #
❸
"created_at": "Wed Mar 23 14:07:43 ...
Become an O’Reilly member and get unlimited access to this title plus top books and audiobooks from O’Reilly and nearly 200 top publishers, thousands of courses curated by job role, 150+ live events each month,
and much more.
Read now
Unlock full access
More than 5,000 organizations count on O’Reilly
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.