Sys.time
Get the Current Date, Time, or Time Zone

Description

Retrieves the current date, time, or time zone or checks the time zone consistency of POSIXt objects.

Usage

Sys.time()
Sys.Date()
date()
Sys.timezone()
check_tzones(...)

Arguments

... objects of classes inherited from POSIXt.

Details

Sys.Date, Sys.time, and Sys.timezone reflect the current system time zone setting (via the TZ environment variable), whereas date always use the default system time zone.
Value
Sys.time returns a POSIXct object representing the current date and time for the current system time zone.
Sys.Date returns a Date object representing the current date for the current system time zone.
date returns a character string representing the current date and time for the default system time zone.
Sys.timezone returns a character string representing the current system time zone (not including the current daylight/standard time status).
check_tzones returns the time zone string of the first object in .... Warns if the time zones are not consistent.
Differences between Spotfire Enterprise Runtime for R and Open-source R
Unlike open-source R, the return value of Spotfire Enterprise Runtime for R's Sys.timezone is platform-independent and matches the value returned in the Windows version of open-source R.
References
Time Zone. http://en.wikipedia.org/wiki/Timezone.
tz database. http://en.wikipedia.org/wiki/Tz_database.
Sources for time zone and daylight saving time data. http://cs.ucla.edu/~eggert/tz/tz-link.htm.
See Also
as.Date, POSIXt, proc.time
Examples
Sys.setenv(TZ = "")
Sys.time(); Sys.Date(); Sys.timezone()
Sys.setenv(TZ = "Asia/Shanghai")
Sys.time(); Sys.Date(); Sys.timezone()
Sys.setenv(TZ = "")

cat('Analysis started ', date(), '...\n', sep='')
# Now perform multi-hour analysis...
cat('Analysis completed ', date(), '.\n', sep='')

x <- Sys.time()
check_tzones(x)
check_tzones(as.POSIXlt(x, tz = "Asia/Shanghai"))
check_tzones(as.POSIXlt(x, tz = "nosuchtimezone"))
check_tzones(as.POSIXlt(x, tz = "Asia/Shanghai"), 
   as.POSIXlt(x, tz = "America/New_York"))
Package base version 6.1.1-7
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