POSIXlt is a list and it is not a list of dates or times, it is a list of > x <- as.POSIXlt(Sys.Date()) > names(x) [1] "sec" "min" "hour" "mday" "mon" "year" "wday" "yday" "isdst"
So if you want to match these things, you should use POSIXct or any other numeric-based format (as POSIXct is just a double value for the number of seconds since 1970-01-01) e.g. > z <- as.POSIXct(Sys.Date()) > x <- as.POSIXct(Sys.Date()) > z==x [1] TRUE > match(z,x) [1] 1 > z %in% x [1] TRUE Dr Oleg Sklyar Research Technologist AHL / Man Investments Ltd +44 (0)20 7144 3803 oskl...@maninvestments.com > -----Original Message----- > From: r-devel-boun...@r-project.org > [mailto:r-devel-boun...@r-project.org] On Behalf Of McGehee, Robert > Sent: 29 June 2010 15:46 > To: r-b...@r-project.org; r-devel@r-project.org > Subject: [Rd] POSIXlt matching bug > > I came across the below mis-feature/bug using match with > POSIXlt objects > (from strptime) in R 2.11.1 (though this appears to be an old issue). > > > x <- as.POSIXlt(Sys.Date()) > > table <- as.POSIXlt(Sys.Date()+0:5) > > length(x) > [1] 1 > > x %in% table # I expect TRUE > [1] FALSE FALSE FALSE FALSE FALSE FALSE FALSE FALSE FALSE > > match(x, table) # I expect 1 > [1] NA NA NA NA NA NA NA NA NA > > This behavior seemed more plausible when the length of a > POSIXlt object > was 9 (back in the day), however since the length was redefined, the > length of x no longer matches the length of the match function output, > as specified by the ?match documentation: "A vector of the same length > as 'x'". > > I would normally suggest that we add a POSIXlt method for match that > converts x into POSIXct or character first. However, match does not > appear to be generic. Below is a possible rewrite of match > that appears > to work as desired. > > match <- function(x, table, nomatch = NA_integer_, > incomparables = NULL) > > .Internal(match(if(is.factor(x)||inherits(x, "POSIXlt")) > as.character(x) else x, > if(is.factor(table)||inherits(table, "POSIXlt")) > as.character(table) else table, > nomatch, incomparables)) > > That said, I understand some people may be very sensitive to the speed > of the match function, and may prefer a simple change to the ?match > documentation noting this (odd) behavior for POSIXlt. > > Thanks, Robert > > R.version > _ > platform x86_64-unknown-linux-gnu > arch x86_64 > os linux-gnu > system x86_64, linux-gnu > status > major 2 > minor 11.1 > year 2010 > month 05 > day 31 > svn rev 52157 > language R > version.string R version 2.11.1 (2010-05-31) > > Robert McGehee, CFA > Geode Capital Management, LLC > One Post Office Square, 28th Floor | Boston, MA | 02109 > Tel: 617/392-8396 Fax:617/476-6389 > mailto:robert.mcge...@geodecapital.com > > > >This e-mail, and any attachments hereto, are intended for use by the > addressee(s) only and may contain information that is (i) confidential > information of Geode Capital Management, LLC and/or its affiliates, > and/or (ii) proprietary information of Geode Capital Management, LLC > and/or its affiliates. If you are not the intended recipient of this > e-mail, or if you have otherwise received this e-mail in error, please > immediately notify me by telephone (you may call collect), or > by e-mail, > and please permanently delete the original, any print outs and any > copies of the foregoing. Any dissemination, distribution or copying of > this e-mail is strictly prohibited. > > ______________________________________________ > R-devel@r-project.org mailing list > https://stat.ethz.ch/mailman/listinfo/r-devel > ********************************************************************** Please consider the environment before printing this email or its attachments. The contents of this email are for the named addressees ...{{dropped:19}} ______________________________________________ R-devel@r-project.org mailing list https://stat.ethz.ch/mailman/listinfo/r-devel
