October 2017
Intermediate to advanced
480 pages
9h 49m
Japanese
Content preview from Rではじめるデータサイエンス
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370
20
章
purrr
と
broom
による多数のモデル
summarize(q = list(quantile(mpg))) %>%
unnest()
#> # A tibble: 15
×
2
#> cyl q
#> <dbl> <dbl>
#> 1 4 21.4
#> 2 4 22.8
#> 3 4 26.0
#> 4 4 30.4
#> 5 4 33.9
#> 6 6 17.8
#> # ... with 9 more rows
4. 次のコードは何をするか。なぜ、これが役立つか。
mtcars %>%
group_by(cyl) %>%
summarize_each(funs(list))
20.5
リスト列を単純化
本書で学んだデータ操作と可視化の技法を応用するには、リスト列を普通の列（アトミックベクト
ル）または列の並びに戻して単純化する必要があります。より単純な構造に戻す
ために使う技法は、
要素に対して単一値を求めるのか、複数値を求めるのかによって異なります。
●
単一値が欲しいなら、アトミックベクトルを作るために
map_lgl()
,
map_int()
,
map_dbl()
,
map_
chr()
で
mutate()
を使う。
●
複数値が欲しいなら、
unnest()
を使ってリスト列を通常の列に戻し、行を必要な回数繰り返す。
次節以降でこれらの詳細を学びます。
20.5.1
リストをベクトルに変換
リスト列をアトミックベクトルにできるとしたら、それは通常の列になります。例えば、オブジェ
クトを型と長 ...
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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.