計算日期時間的差值

在 R 中處理日期與時間

Charlotte Wickham

Instructor

日期時間的運算

releases <- read_csv("rversions.csv")
last_release <- filter(releases, date == max(date))

Sys.Date() - last_release$date

Time difference of 99 days

difftime(Sys.Date(), last_release$date)

Time difference of 99 days

time1 - time2 與 difftime(time1, time2) 等價。

units = "secs"、"mins"、"hours"、"days" 或 "weeks"

difftime(Sys.Date(), last_release$date, units = "secs")

Time difference of 8553600 secs

difftime(Sys.Date(), last_release$date, units = "weeks")

Time difference of 14.14286 weeks

today()

"2017-10-07"

str(today())

 Date[1:1], format: "2017-10-07"

now()

"2017-10-07 09:44:52 PDT"

str(now())

 POSIXct[1:1], format: "2017-10-07 09:44:59"

在 R 中處理日期與時間