> On Apr 14, 2018, at 12:18 PM, WRAY NICHOLAS via R-help <r-help@r-project.org> > wrote: > > > -------- Original Message ---------- > From: WRAY NICHOLAS <nicholas.w...@ntlworld.com> > To: peter dalgaard <pda...@gmail.com> > Date: 14 April 2018 at 20:18 > Subject: Re: [R] Reading xpt files into R > > > Well yesterday I'd downloaded the "foreign" package and tried to open the xpt > file using that: > > library(foreign) > read.xport("test.xpt") > > I got the following error and warning messages: > >> read.xport("test.xpt") > Error in read.xport("test.xpt") : > The specified file does not start with a SAS xport file header! > In addition: Warning message: > In readBin(file, what = character(0), n = 1, size = nchar(xport.file.header, > : > null terminator not found: breaking string at 10000 bytes > > I can open the xpt using wordpad and there is a header but it seems to be > just text. I really don't know what constitutes an " > SAS xport file header"
I'm not sure why Peter deleted my copy of a sample of a SAS xport header that I took from an NHANES data distribution. He seemed to think I was confused about the function you had been using. The reason I mentioned that `read.xport` was from the 'foreign' package is that one generally loads that package to make the function available, while it appears you were using a different package, SASxport, and I didn't know whether that package had a function which had the same name as the one from pkg-foreign, and if it did whether it might depend on the read.xport function in foreign. You should not need to download the 'foreign' package, since it ships with every distribution of R. These are the arguments accepted by that function: SASxport::read.xport function (file, force.integer = TRUE, formats = NULL, name.chars = NULL, names.tolower = FALSE, keep = NULL, drop = NULL, as.is = 0.95, verbose = FALSE, as.list = FALSE, include.formats = FALSE) When I look at the SASxport::read.xport function code, it is in fact, _not_ the same function. But it does have the R statement about what it thinks qualifies as a SAS xprot file: xport.file.header <- "HEADER RECORD*******LIBRARY HEADER RECORD!!!!!!!000000000000000000000000000000 " It checks to see whether the file starts with that string. This is what appeared in my first message: > > The "export" or "transfer format from SA is supposed to make reading data > less difficult and standardized. This is what a header from the version used > by the NHANES releases (that's all one line): > > HEADER RECORD*******LIBRARY HEADER > RECORD!!!!!!!000000000000000000000000000000 SAS SAS SASLIB 9.2 > XP_PRO 16SEP09:09:39:2516SEP09:09:39:25 > HEADER RECORD*******MEMBER > HEADER RECORD!!!!!!!000000000000000001600000000140 HEADER > RECORD*******DSCRPTR HEADER RECORD!!!!!!!000000000000000000000000000000 SAS > DEMO SASDATA 9.2 XP_PRO > 16SEP09:09:39:2516SEP09:09:39:25 > HEADER RECORD*******NAMESTR HEADER > RECORD!!!!!!!000000014400000000000000000000 SEQN Respondent sequence > number So the header is text, but it is text with a particular structure. If your file doesn't have that structure, then it's not a SAS xport file. The .xpt extension is also used for Mozilla Firefox plugins. > > Nick > > > > On 14 April 2018 at 10:32 peter dalgaard <pda...@gmail.com> wrote: > > That's what he tried, Actually not, Peter. Wray was using a function of the same name, but not from pkg-foreign. Perhaps he was following the tutorial at: http://www.phusewiki.org/wiki/index.php?title=Open_XPT_File_with_R > but the bottom line is that just because something is called foo.xpt there is > no guarantee that it actually is a SAS XPORT file. Firefox plugins use the > same extension but it could really be anything - naming conventions are just > that: conventions. > > So dig deeper and find out what the file really is (or was supposed to be). Peter and I agree agree on that advice. > > -pd > >> >> On 14 Apr 2018, at 00:18 , David Winsemius >> <dwinsem...@comcast.net> wrote: >> >> There is a read.xport function in the foreign package and I think >> most people would have chosen that one as a first attemp. It's part of the >> standard R distribution. It refers you to >> https://support.sas.com/techsup/technote/ts140.pdf for details on the format. > -- David Winsemius Alameda, CA, USA 'Any technology distinguishable from magic is insufficiently advanced.' -Gehm's Corollary to Clarke's Third Law ______________________________________________ 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.