'Rcpp' Access to the 'CCTZ' timezone library is provided. 'CCTZ' is a C++ library for translating between absolute and civil times using the rules of a time zone. The 'CCTZ' source code, released under the Apache 2.0 License, is included in this package. See < https://github.com/google/cctz> for more details.
Rcpp bindings for CCTZ
CCTZ (C++ Time Zone) is an excellent (yet small) C++11 library for translating between absolute times and civil times using the rules defined by a time zone. See its repository (as well as code) for very detailed documentation. CCTZ is being developed by Google but not an officially endorsed product.
This package wraps CCTZ for use by R via Rcpp.
R> # simple call: difference nowR> tzDiff("America/New_York", "Europe/London", Sys.time())[1] 5R> # tabulate difference for every week of the yearR> table(sapply(0:52, function(d) tzDiff("America/New_York", "Europe/London",+ as.POSIXct(as.Date("2016-01-01") + d*7)))) 4 5 3 50 R> # Given current time in NY what is the time London, UKR> # (running the code locally in Chicago hence CST text format) R> toTz(Sys.time(), "America/New_York", "Europe/London") [1] "2016-12-10 17:15:04.20370 CST"R> # this redoes the 'Armstrong on the moon in NYC and Sydney' exampleR> # note that the default print method will print the return object in _your local time_R> toTz(ISOdatetime(1969,7,20,22,56,0,tz="UTC"), "America/New_York", "Australia/Sydney", TRUE)1969-07-20 22:56:00 -04001969-07-21 12:56:00 +1000[1] "1969-07-20 21:56:00 CDT"R> # whereas explicitly formating for Sydney time does the right thingR> format(toTz(ISOdatetime(1969,7,20,22,56,0,tz="UTC"), + "America/New_York", "Australia/Sydney", verbose=TRUE), + tz="Australia/Sydney")1969-07-20 22:56:00 -04001969-07-21 12:56:00 +1000[1] "1969-07-21 12:56:00"R> now <- Sys.time()R> formatDatetime(now) # current (UTC) time, in full precision RFC3339[1] "2016-12-10T18:23:03.327956+00:00"R> formatDatetime(now, tgttzstr="America/New_York") # same but in NY[1] "2016-12-10T13:23:03.327956-05:00"R> formatDatetime(now + 0:4) # vectorised[1] "2016-12-10T18:23:03.327956+00:00" "2016-12-10T18:23:04.327956+00:00" [3] "2016-12-10T18:23:05.327956+00:00" "2016-12-10T18:23:06.327956+00:00"[5] "2016-12-10T18:23:07.327956+00:00"R> R> ds <- getOption("digits.secs")R> options(digits.secs=6) # max valueR> parseDatetime("2016-12-07 10:11:12", "%Y-%m-%d %H:%M:%S"); # full seconds[1] "2016-12-07 04:11:12 CST"R> parseDatetime("2016-12-07 10:11:12.123456", "%Y-%m-%d %H:%M:%E*S"); # fractional seconds[1] "2016-12-07 04:11:12.123456 CST"R> parseDatetime("2016-12-07T10:11:12.123456-00:00") ## default RFC3339 format[1] "2016-12-07 04:11:12.123456 CST"R> now <- trunc(Sys.time())R> parseDatetime(formatDatetime(now + 0:4)) # vectorised[1] "2016-12-10 12:24:25 CST" "2016-12-10 12:24:26 CST" "2016-12-10 12:24:27 CST"[4] "2016-12-10 12:24:28 CST" "2016-12-10 12:24:29 CST"R> options(digits.secs=ds) The CCTZ library depends on timezone files typically found in
/usr/share/zoneinfo which requires a Unix-alike OS such as Linux or OS X. Old school Unix variants
may work.
On CRAN, builds and tests cleanly, and the example functions are accessible from R.
Dirk Eddelbuettel
GPL (>= 2)