chron: Chronological Objects which can Handle Dates and Times

> library(chron)

バージョン: 2.3.47

関数名	概略
`as.chron.yearmon`	Convert monthly or quarterly data to chron
`chron`	Create a Chronological Object
`chron_trans`	Coordinates and Positions for Chronological Objects
`cut.dates`	Create a Factor from a Chron or Dates Object
`dates`	Generate Dates and Times Components from Input
`day.of.week`	Convert between Julian and Calendar Dates
`days`	Return Various Periods from a Chron or Dates Object
`format.chron`	Format a chron object
`hours`	Return Hours, Minutes, or Seconds from a Times Object
`is.holiday`	Find Weekends and Holidays in a Chron or Dates Object
`seq.dates`	Generate Chron or Dates Sequences
`trunc.times`	Truncate times Objects

dates / times

日付、時間要素の生成

> c("09/01/15", "09/02/15") %>% class()

[1] "character"

> dates(c("09/01/15", "09/02/15")) %>% class()

[1] "dates" "times"

> times(c("20:47:00", "20:47:01")) %>% class()

[1] "times"

連続的な時間オブジェクトを生成する

> seq.dates("01/01/92", "12/31/92", by = "months")

 [1] 01/01/92 02/01/92 03/01/92 04/01/92 05/01/92 06/01/92 07/01/92
 [8] 08/01/92 09/01/92 10/01/92 11/01/92 12/01/92

> head(AirPassengers)

[1] 112 118 132 129 121 135

> head(as.chron(AirPassengers))

[1] 01/01/49 02/01/49 03/01/49 04/01/49 05/01/49 06/01/49