Описание тега posixct
In the R language, the classes "POSIXct" and "POSIXlt" are representing calendar dates and times (to the nearest second).
The classes POSIXct
and POSIXlt
are representing calendar dates and times in R.
The class POSIXct
represents the (signed) number of seconds since the beginning of 1970 (in the UTC timezone) as a numeric vector.
Class POSIXlt
is a named list of vectors representing
- sec: seconds (0-61)
- min: minutes (0-59)
- hour: hours (0-23)
- mday: day of the month (1-31)
- mon: months after the first of the year (0-11)
- year: years since 1900
- wday: day of the week, starting on Sunday (0-6)
- yday: day of the year (0-365)
- isdst: Daylight Savings Time flag. Positive if in force, zero if not, negative if unknown.
POSIXct
is more convenient for including in data frames, and POSIXlt
is closer to human-readable forms. A virtual class POSIXt
exists from which both of the classes inherit.
References:
- Ripley, B. D. and Hornik, K. (2001) Date-time classes. R News, 1/2, 8–11.