| Type: | Package |
| Title: | 'Rcpp' Bindings for the 'CCTZ' Library |
| Version: | 0.2.13 |
| Date: | 2024-12-11 |
| Description: | '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. |
| License: | GPL-2 | GPL-3 [expanded from: GPL (≥ 2)] |
| Imports: | Rcpp (≥ 0.11.0) |
| Suggests: | tinytest |
| LinkingTo: | Rcpp |
| SystemRequirements: | A 64-bit POSIX OS such as Linux or OS X with IANA time zone data in /usr/share/zoneinfo as well as a recent-enough C++11 compiler (such as g++-4.9 or later which is preferred, g++-4.8 works too). On Windows the zoneinfo included with R is used; and time parsing support is enabled via a backport of std::get_time from the LLVM libc++ library. |
| URL: | https://github.com/eddelbuettel/rcppcctz, https://dirk.eddelbuettel.com/code/rcpp.cctz.html |
| BugReports: | https://github.com/eddelbuettel/rcppcctz/issues |
| RoxygenNote: | 6.0.1 |
| NeedsCompilation: | yes |
| Packaged: | 2024-12-12 01:32:20 UTC; edd |
| Author: | Dirk Eddelbuettel 
[aut, cre],
Bradley White [aut] (Principal author of CCTZ) |
| Maintainer: | Dirk Eddelbuettel <edd@debian.org> |
| Repository: | CRAN |
| Date/Publication: | 2024-12-12 04:40:08 UTC |
A Simple Wrapper to the CCTZ Library for Time Zone Calculations
Description
CCTZ contains two underlying libraries which build on the C++11
library chrono. The first covers civil time for
computing with human-scale time such as dates and time. It is
header-only. The second covers time zones and allow translation
between absolute time and civil time.
RcppCCTZ brings CCTZ to R by means of Rcpp.
Details
CCTZ requires a valid timezone library as well as recent-enough compiler to cope with C++11.
Windows is supported since version 0.2.0 via the g++-4.9
compiler, but note that it provides an incomplete C++11
library. The std::get_time function was ported from libc++ of
the LLVM to enable this. However, string formatting is more limited as
the libc++ library used by g++-4.9 does not provide complete
C++11 semantics. As one example, CCTZ frequently uses "%F %T"
which do not work on Windows; one has to use
"%Y-%m-%d %H:%M:%S".
Author(s)
Dirk Eddelbuettel wrote the package; Dan Dillon ported std::get_time
from LLVM's libc++; Bradley White and Greg Miller wrote the underlying CCTZ library.
Maintainer: Dirk Eddelbuettel <edd@debian.org>
References
The CCZT repository at https://github.com/google/cctz has additional information.
Examples
helloMoon()
Format a Datetime vector as a string vector
Description
Format a Datetime vector
Usage
formatDatetime(dtv, fmt = "%Y-%m-%dT%H:%M:%E*S%Ez", lcltzstr = "UTC",
tgttzstr = "UTC")
formatDouble(secv, nanov, fmt = "%Y-%m-%dT%H:%M:%E*S%Ez",
tgttzstr = "UTC")
Arguments
dtv |
A Datetime vector object to be formatted |
fmt |
A string with the format, which is based on |
lcltzstr |
The local timezone object for creation the CCTZ timepoint |
tgttzstr |
The target timezone for the desired format |
secv |
A numeric vector with seconds since the epoch |
nanov |
A numeric vector with nanoseconds since the epoch,
complementing |
Details
An alternative to format.POSIXct based on the CCTZ library. The
formatDouble variant uses two vectors for seconds since the epoch
and fractional nanoseconds, respectively, to provide fuller resolution.
Value
A string vector with the requested format of the datetime objects
Note
Windows is now supported via the g++-4.9 compiler, but note
that it provides an incomplete C++11 library. This means we had
to port a time parsing routine, and that string formatting is more
limited. As one example, CCTZ frequently uses "%F %T" which do
not work on Windows; one has to use "%Y-%m-%d %H:%M:%S".
Author(s)
Dirk Eddelbuettel
Examples
## Not run:
now <- Sys.time()
formatDatetime(now) # current (UTC) time, in full precision RFC3339
formatDatetime(now, tgttzstr="America/New_York") # same but in NY
formatDatetime(now + 0:4) # vectorised
## End(Not run)
Parse a Datetime vector from a string vector
Description
Parse a Datetime vector
Usage
parseDatetime(svec, fmt = "%Y-%m-%dT%H:%M:%E*S%Ez", tzstr = "UTC")
parseDouble(svec, fmt = "%Y-%m-%dT%H:%M:%E*S%Ez", tzstr = "UTC")
Arguments
svec |
A string vector from which a Datetime vector is to be parsed |
fmt |
A string with the format, which is based on |
tzstr |
The local timezone for the desired format |
Details
An alternative to as.POSIXct based on the CCTZ library
Value
A Datetime vector object for parseDatetime, a numeric matrix with
two columns for seconds and nanoseconds for parseDouble
Author(s)
Dirk Eddelbuettel
Examples
ds <- getOption("digits.secs")
options(digits.secs=6) # max value
parseDatetime("2016-12-07 10:11:12", "%Y-%m-%d %H:%M:%S") # full seconds
parseDatetime("2016-12-07 10:11:12.123456", "%Y-%m-%d %H:%M:%E*S") # fractional seconds
parseDatetime("2016-12-07T10:11:12.123456-00:00") ## default RFC3339 format
parseDatetime("20161207 101112.123456", "%E4Y%m%d %H%M%E*S") # fractional seconds
now <- trunc(Sys.time())
parseDatetime(formatDatetime(now + 0:4)) # vectorised
options(digits.secs=ds)
Shift datetime object from one timezone to another
Description
Change from one given timezone to another.
Usage
toTz(dtv, tzfrom, tzto, verbose = FALSE)
Arguments
dtv |
A DatetimeVector object specifying when the difference is to be computed. |
tzfrom |
The first time zone as a character vector. |
tzto |
The second time zone as a character vector. |
verbose |
A boolean toggle indicating whether more verbose operations
are desired, default is |
Details
Time zone offsets vary by date, and this helper function converts a Datetime object from one given timezone to another.
Value
A DatetimeVector object with the given (civil time) determined by the incoming object (and its timezone) shifted to the target timezone.
Author(s)
Dirk Eddelbuettel
Examples
## Not run:
toTz(Sys.time(), "America/New_York", "Europe/London")
# this redoes the 'Armstrong on the moon in NYC and Sydney' example
toTz(ISOdatetime(1969,7,20,22,56,0,tz="UTC"), "America/New_York", "Australia/Sydney", verbose=TRUE)
# we can also explicitly format for Sydney time
format(toTz(ISOdatetime(1969,7,20,22,56,0,tz="UTC"),
"America/New_York", "Australia/Sydney", verbose=TRUE),
tz="Australia/Sydney")
## End(Not run)
Return difference between two time zones at a given date.
Description
Difference between two given timezones at a specified date.
Usage
tzDiff(tzfrom, tzto, dt, verbose = FALSE)
Arguments
tzfrom |
The first time zone as a character vector. |
tzto |
The second time zone as a character vector. |
dt |
A Datetime object specifying when the difference is to be computed. |
verbose |
A boolean toggle indicating whether more verbose operations
are desired, default is |
Details
Time zone offsets vary by date, and this helper function computes the difference (in hours) between two time zones for a given date time.
Value
A numeric value with the difference (in hours) between the first and second time zone at the given date
Author(s)
Dirk Eddelbuettel
Examples
## Not run:
# simple call: difference now
tzDiff("America/New_York", "Europe/London", Sys.time())
# tabulate difference for every week of the year
table(sapply(0:52, function(d) tzDiff("America/New_York", "Europe/London",
as.POSIXct(as.Date("2016-01-01") + d*7))))
## End(Not run)