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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13.2
日付
/
時刻の作成
209
あります。要素の順序を指定すれば、自動的にフォーマットします。使うためには、日付の年、月、
日をそれぞれ
"y"
,
"m"
,
"d"
で表します。これで日付をパースする
lubridate
関数の名前がわかりま
す。
ymd("2017-01-31")
#> [1] "2017-01-31"
mdy("January 31st, 2017")
#> [1] "2017-01-31"
dmy("31-Jan-2017")
#> [1] "2017-01-31"
これらの関数は引用符なしの数も取ります。日付時刻データをフィルタする必要がある場合、単一
の日付時刻データを作るのに最も簡単な方法です。
ymd()
が簡潔で曖昧さがありません。
ymd(20170131)
#> [1] "2017-01-31"
ymd()
とその同類が日付を作成します。日付時刻を作るには、関数名にアンダースコアと「h」、
「m」
、「s」の組み合わせを付けてパース関数にします。
ymd_hms("2017-01-31 20:11:59")
#> [1] "2017-01-31 20:11:59 UTC"
mdy_hm("01/31/2017 08:01")
#> [1] "2017-01-31 08:01:00 UTC"
タイムゾーンを引数に指定して日付から日付時刻を作ることもできます。
ymd(20170131, tz = "UTC")
#> [1] "2017-01-31 UTC"
13.2.2
個別要素から作成
単一文字列の ...
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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.