Thanks for the report. Should be fixed in teh devel and 2.9 branches.
luke On Mon, 1 Jun 2009, William Dunlap wrote:
It looks like the 'seq' variable to 'for' can be altered from within the loop, leading to incorrect answers. E.g., in the following I'd expect 'sum' to be 1+2=3, but R 2.10.0 (svn 48686) gives 44.5. > x = c(1,2); sum = 0; for (i in x) { x[i+1] = i + 42.5; sum = sum + i }; sum [1] 44.5 or, with a debugging cat()s, > x = c(1,2); sum = 0; for (i in x) { cat("before, i=", i, "\n"); x[i+1] = i + 42.5; cat("after, i=", i,"\n"); sum = sum + i }; sum before, i= 1 after, i= 1 before, i= 43.5 after, i= 43.5 [1] 44.5 If I force the for's 'seq' to be a copy of x by adding 0 to it, then I do get the expected answer. > x = c(1,2); sum = 0; for (i in x+0) { x[i+1] = i + 42.5; sum = sum + i }; sum bbbbb[1] 3 It looks like an error in reference counting. Bill Dunlap TIBCO Software Inc - Spotfire Division wdunlap tibco.com ______________________________________________ R-devel@r-project.org mailing list https://stat.ethz.ch/mailman/listinfo/r-devel
-- Luke Tierney Chair, Statistics and Actuarial Science Ralph E. Wareham Professor of Mathematical Sciences University of Iowa Phone: 319-335-3386 Department of Statistics and Fax: 319-335-3017 Actuarial Science 241 Schaeffer Hall email: l...@stat.uiowa.edu Iowa City, IA 52242 WWW: http://www.stat.uiowa.edu ______________________________________________ R-devel@r-project.org mailing list https://stat.ethz.ch/mailman/listinfo/r-devel