RcppCCTZ: Rcpp bindings forCCTZ
What is CCTZ?
CCTZ (C++ Time Zone) isan excellent (yet small) C++11 library for translating between absolutetimes and civil times using the rules defined by a time zone. See itsrepository (as well as code)for very detailed documentation.CCTZ is being developed byGoogle but not an officially endorsed product.
What is RcppCCTZ?
This package wraps CCTZ for use by R viaRcpp.
Examples
Difference between Timezones
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))))45350Shifting Timezone
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)1969-07-2022:56:00-04001969-07-2112:56:00+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")1969-07-2022:56:00-04001969-07-2112:56:00+1000[1]"1969-07-21 12:56:00"Parsing and Formatting
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)Requirements
TheCCTZ library dependson timezone files typically found in/usr/share/zoneinfowhich requires a Unix-alike OS such as Linux or OS X. Old school Unixvariants may work.
Status
OnCRAN,builds and tests cleanly, and the example functions are accessible fromR.
Installation
The package is now onCRANand can be installed via a standard
install.packages("RcppCCTZ")Continued Testing
As we rely on thetinytest package,the already-installed package can also be verified via
tinytest::test_package("RcppCCTZ")at any later point.
Author
Dirk Eddelbuettel
License
GPL (>= 2)
Initially created: Thu Jul 14 06:19:32 CDT 2016
Last modified: Sun May 26 10:09:44 CDT 2024