On Wed, Feb 3, 2016 at 3:43 PM, Jeff Newmiller <jdnew...@dcn.davis.ca.us> wrote: > Not exactly. > > If you have been "Excel"ed and have both formats in one column then you > really have a data cleanup task to do.
No need to reinvent the wheel. Just do library(lubridate) mdy(c("09/01/15", "09/01/2015")) Best, ista The best route to resolution is to > fix the source of the data (e.g. go back into Excel and reformat the column > with consistent formatting). > > If you need to do this on an ongoing basis and cannot fix the data source, > then you might need to choose the correct format on the fly... something > like: > > yYdates <- function( ds ) { > fmt <- ifelse( grepl( "^\\d{1,2}/\\d{1,2}/\\d{2}$", ds ) > , "%m/%d/%y" > , "%m/%d/%Y" > ) > as.Date( ds, format=fmt ) > } > > yYdates( c( "02/18/2015", "03/21/16" ) ) > [1] "2015-02-18" "2016-03-21" > > but this would have to be tailored to the formatting problems in your data > and is not really a general solution. > > On Wed, 3 Feb 2016, Boris Steipe wrote: > >> As the documentation says, that's exactly what the expansion will do by >> default. >> >> B. >> >> >> On Feb 3, 2016, at 2:31 PM, carol white <wht_...@yahoo.com> wrote: >> >>> yes, some of them are like 09/01/15 and some others are 09/01/2015 and >>> all of them range between 2015 and 2016. The goal was to convert 09/01/15 to >>> 09/01/2015. I don't know if the fact that they range between 2015 and 2016 >>> make the task easier. >>> >>> Best wishes >>> Carol >>> >>> >>> On Wednesday, February 3, 2016 7:34 PM, Boris Steipe >>> <boris.ste...@utoronto.ca> wrote: >>> >>> >>> Sorry - messed up example: corrected here... >>> >>> d <- "7/27/77" >>> strptime(d, format="%m/%d/%y") # "1977-07-27 EDT" >>> x <- strptime(d, format="%m/%d/%y") >>> >>> strftime(x, format="%m/%d/%Y") # "07/27/1977" >>> >>> >>> On Feb 3, 2016, at 1:29 PM, Boris Steipe <boris.ste...@utoronto.ca> >>> wrote: >>> >>>> It seems your autocorrect is playing tricks on you but if I understand >>>> you correctly you have a two digit year and want to convert that to a four >>>> digit year? That's not uniquely possible of course; by convention, as the >>>> documentation to strptime() says: >>>> >>>> On input, values 00 to 68 are prefixed by 20 and 69 to 99 by 19 ? that >>>> >>>> is the behaviour specified by the 2004 and 2008 POSIX standards... >>>> >>>> If this is correct for you, you need to convert the string to a time >>>> object and the time object back to string. The format specifier %Y prints >>>> four-digit years: >>>> >>>> >>>> d <- "7/27/59" >>>> strptime(d, format="%m/%d/%y") # "2059-07-27 EDT" >>>> x <- strptime(d, format="%m/%d/%y") >>>> >>>> strftime(x, format="%m/%d/%Y") # "07/27/1977" >>>> >>>> >>>> >>>> B. >>>> >>>> >>>> >>>> >>>> >>>> >>>> >>>> On Feb 3, 2016, at 11:03 AM, carol white via R-help >>>> <r-help@r-project.org> wrote: >>>> >>>>> Hi,might be trivial but how to determine the year of a date which is in >>>>> the %m/%d/%y format and those whose year is century should be modified to >>>>> ISO so that all date will have with year in ISO? >>>>> Regards, >>>>> Carol >>>>> >>>>> [[alternative HTML version deleted]] >>>>> >>>>> ______________________________________________ >>>>> R-help@r-project.org mailing list -- To UNSUBSCRIBE and more, see >>>>> https://stat.ethz.ch/mailman/listinfo/r-help >>>>> PLEASE do read the posting guide >>>>> http://www.R-project.org/posting-guide.html >>>>> and provide commented, minimal, self-contained, reproducible code. >>> >>> >>>> >>>> ______________________________________________ >>>> R-help@r-project.org mailing list -- To UNSUBSCRIBE and more, see >>>> https://stat.ethz.ch/mailman/listinfo/r-help >>>> PLEASE do read the posting guide >>>> http://www.R-project.org/posting-guide.html >>>> and provide commented, minimal, self-contained, reproducible code. >>> >>> >>> >> >> ______________________________________________ >> R-help@r-project.org mailing list -- To UNSUBSCRIBE and more, see >> https://stat.ethz.ch/mailman/listinfo/r-help >> PLEASE do read the posting guide >> http://www.R-project.org/posting-guide.html >> and provide commented, minimal, self-contained, reproducible code. >> > > --------------------------------------------------------------------------- > Jeff Newmiller The ..... ..... Go Live... > DCN:<jdnew...@dcn.davis.ca.us> Basics: ##.#. ##.#. Live Go... > Live: OO#.. Dead: OO#.. Playing > Research Engineer (Solar/Batteries O.O#. #.O#. with > /Software/Embedded Controllers) .OO#. .OO#. rocks...1k > > > ______________________________________________ > R-help@r-project.org mailing list -- To UNSUBSCRIBE and more, see > https://stat.ethz.ch/mailman/listinfo/r-help > PLEASE do read the posting guide http://www.R-project.org/posting-guide.html > and provide commented, minimal, self-contained, reproducible code. ______________________________________________ R-help@r-project.org mailing list -- To UNSUBSCRIBE and more, see https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide http://www.R-project.org/posting-guide.html and provide commented, minimal, self-contained, reproducible code.