January 2020
Intermediate to advanced
584 pages
7h 18m
Japanese
Content preview from Rクックブック 第2版
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12章便利なテクニック
本章のレシピは、わかりにくい数値計算や難しい統計学的手法ではなく、頻繁に必要となる便利な関数や、よく使われるテクニックです。
レシピ12.1 データの一部を表示する
問題
データが多すぎて一度には表示できない。データの一部を確認したい。
解決策
headを使うと、データの最初の数行を表示できます。
head(x)
tailを使うと、データの最後の数行を表示できます。
tail(x)
または、RStudioのインタラクティブビューアで全体を表示することもできます。
View(x)
解説
大量のデータセットを出力しても、すべてが画面上を流れて行ってしまうだけで意味がありません。headを使うと、データの一部が表示できます（デフォルトでは6行）。
load(file = './data/lab_df.rdata')head(lab_df)## x lab y ## 1 0.0761 NJ 1.621 ## 2 1.4149 KY 10.338 ## 3 2.5176 KY 14.284 ## 4 -0.3043 KY 0.599 ## 5 2.3916 KY 13.091 ## 6 2.0602 NJ 16.321
tailを使うと、最後の数行とその行番号が表示できます。
tail(lab_df)
## x lab y
## 195 7.353 KY 38.880
## 196 -0.742 KY -0.298
## 197 2.116 NJ 11.629
## 198 1.606 KY 9.408
## 199 -0.523 KY -1.089
## 200 0.675 KY 5.808
headとtailは、どちらも数値を渡して返す行を指定できます。 ...
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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.