日時の丸め処理

Rで扱う日付と時刻

Charlotte Wickham

Instructor

丸め処理と抽出の違い

release_time <- releases$datetime
head(release_time)

"1997-12-04 08:47:58 UTC" "1997-12-21 13:09:22 UTC"
"1998-01-10 00:31:55 UTC" "1998-03-14 19:25:55 UTC"
"1998-05-02 07:58:17 UTC" "1998-06-14 12:56:20 UTC"

head(release_time) %>% hour()

8 13  0 19  7 12

head(release_time) %>% floor_date(unit = "hour")

"1997-12-04 08:00:00 UTC" "1997-12-21 13:00:00 UTC"
"1998-01-10 00:00:00 UTC" "1998-03-14 19:00:00 UTC"
"1998-05-02 07:00:00 UTC" "1998-06-14 12:00:00 UTC"

lubridate の丸め処理

round_date() - 最も近い単位に丸める
ceiling_date() - 切り上げ
floor_date() - 切り捨て
unit に指定可能な値:
- "second", "minute", "hour", "day", "week", "month", "bimonth", "quarter", "halfyear", または "year".
- 倍数も指定可能（例: "2 years", "5 minutes"）

練習しましょう！

Rで扱う日付と時刻