On Dec 11, 2010, at 08:23 , Niels Richard Hansen wrote: > Dear R developers > > Using the 'foreach' package I encounter warnings like > > Warning message: > In identical(.combine, cbind) : ignoring non-pairlist attributes > > Warnings appear once in a new R-session when I run a > particular piece of code - and not again. I understand from > the source code of 'identical' that the function checks and > believes that .combine and cbind have non-pairlist attributes, but I > don't understand how this can be the case > > I have produced the following minimal example > > data.frame()[rep(1,1e6), ] > library(foreach) > identical(foreach:::defcombine, cbind) > > resulting in > > [1] FALSE > Warning message: > In identical(foreach:::defcombine, cbind) : > ignoring non-pairlist attributes > > The warning is not related to the foreach package it seems. I get > the same kind of warning with e.g. > > identical(spatial:::trmat, cbind) > > in a new R-session. Many other functions I have tried do, however, > not result in the warning. The warning depends on the supposedly completely > unrelated data frame operation. It seems also to be related to the > fact that the data frame is empty and I extract a large number of > columns out of this empty data frame. I would highly appreciate help > on this to get rid of the warning in my own package.
Hm, I think you might have tickled a buglet here. I can debug it down to a comparison of two CHARSXPs, both having CHARSXP attributes. I'm a getting a little rusty on debugging at that level, but I don't think CHARSXPs are supposed to _have_ attributes in any meaningful context, so perhaps identical() just shouldn't check. On the other hand, it could also be the sign of a memory overrun in the preceding memory-intensive operation. -- Peter Dalgaard Center for Statistics, Copenhagen Business School Solbjerg Plads 3, 2000 Frederiksberg, Denmark Phone: (+45)38153501 Email: pd....@cbs.dk Priv: pda...@gmail.com ______________________________________________ R-devel@r-project.org mailing list https://stat.ethz.ch/mailman/listinfo/r-devel
