Anything to 'POSIXct' or 'Date' Converter
Convert input in any one of character, integer, numeric, factor, or ordered type into 'POSIXct' (or 'Date') objects, using one of a number of predefined formats, and relying on Boost facilities for date and time parsing.
R excels at computing with dates, and times. Using typed representation for your data is highly recommended not only because of the functionality offered but also because of the added safety stemming from proper representation.
But there is a small nuisance cost in interactive work as well as in
programming. How often have we told
as.POSIXct() that the origin is
(of course) the epoch. Do we
really have to say it again? Similarly, when parsing dates that are
somewhat in YYYYMMDD format, do we really need to bother converting
from integer or numeric or character or factor or ordered with one of
dozen separators and/or month forms: YYYY-MM-DD, YYYY/MM/DD, YYYYMMDD,
YYYY-mon-DD and so on?
So there may have been a need for a general purpose converter
returning a proper
Date) object no matter the input
(provided it was somewhat parseable).
anytime() tries to be that
The actual conversion is done by a combination of Boost lexical_cast to go from (almost) anything to string representation which is then parsed by Boost Date_Time. An alternate method using the corresponding R functions is also available as a fallback.
Conversion is done by looping over a fixed set of formats until a
matching one is found, or returning an error if none is found. The
current set of conversion formulae is accessible in the source
and can now also be accessed in R via
getFormats(). Formats can be
added and removed via the
Details on the Boost date format symbols are provided by the Boost
and similar (but not identical) to what
Boost date_time: https://www.boost.org/doc/libs/1_70_0/doc/html/date_time.html
Boost format documentation: https://www.boost.org/doc/libs/1_61_0/doc/html/date_time/date_time_io.html#date_time.format_flags
Sys.setenv(TZ=anytime:::getTZ()) ## helper function to try to get TZ options(digits.secs=6) ## for fractional seconds below library(anytime) ## load package, caches TZ information ## integer anydate(20160101L + 0:2) ## numeric anydate(20160101 + 0:2) ## factor anydate(as.factor(20160101 + 0:2)) ## ordered anydate(as.ordered(20160101 + 0:2)) ## Dates: Character anydate(as.character(20160101 + 0:2)) ## Dates: alternate formats anydate(c("20160101", "2016/01/02", "2016-01-03")) ## Datetime: ISO with/without fractional seconds anytime(c("2016-01-01 10:11:12", "2016-01-01 10:11:12.345678")) ## Datetime: ISO alternate (?) with 'T' separator anytime(c("20160101T101112", "20160101T101112.345678")) ## Short month '%b' (and full month is supported too) anytime(c("2016-Sep-01 10:11:12", "Sep/01/2016 10:11:12", "Sep-01-2016 10:11:12")) ## Datetime: Mixed format (cf https://stackoverflow.com/questions/39259184) anytime(c("Thu Sep 01 10:11:12 2016", "Thu Sep 01 10:11:12.345678 2016"))