But in 2.10.1 patched
z=function(x){x*2}
z()
Error in x * 2 : 'x' is missing
[See the posting guide about checking current versions before posting ... My notes say the change was in 2.8.0 and a side effect of something else rather than deliberate.]
On Thu, 28 Jan 2010, Barry Rowlingson wrote:
Back in the days of R 2.6, if you did this, you got this:z=function(x){x*2} z()Error in z() : argument "x" is missing, with no default But now in this decade we get (for R 2.9 and 2.10):z=function(x){x*2} z()Error in z() : element 1 is empty; the part of the args list of '*' being evaluated was: (x, 2) Now I can see (after thinking about it) that what is happening is that because of lazy evaluation or something the 'x' isn't getting spotted as being empty until R tries to do x*2, which obviously maps to *(x,2) in functional form. It's perfectly correct to say element 1 of the args list of '*', being (x,2), is empty. But which of those two errors above is clearer? I don't suppose much can be done about this since it is going to the guts of modern R, and I was surprised my initial searches didn't find hordes of confused newbies. Just me then. It got me when I was doing a histogram of some dates:hist(cases)Error in inherits(breaks, "POSIXt") : element 1 is empty; the part of the args list of '.Internal' being evaluated was: (x, what, which) who what which? If the error had been "Error in hist(cases): argument 'breaks' is missing, with no default" you wouldn't be wasting your time reading this now... Barry -- blog: http://geospaced.blogspot.com/ web: http://www.maths.lancs.ac.uk/~rowlings web: http://www.rowlingson.com/ twitter: http://twitter.com/geospacedman pics: http://www.flickr.com/photos/spacedman ______________________________________________ R-devel@r-project.org mailing list https://stat.ethz.ch/mailman/listinfo/r-devel
-- Brian D. Ripley, rip...@stats.ox.ac.uk Professor of Applied Statistics, http://www.stats.ox.ac.uk/~ripley/ University of Oxford, Tel: +44 1865 272861 (self) 1 South Parks Road, +44 1865 272866 (PA) Oxford OX1 3TG, UK Fax: +44 1865 272595 ______________________________________________ R-devel@r-project.org mailing list https://stat.ethz.ch/mailman/listinfo/r-devel
