Tried the following with R --vanilla on the Rv2.4.0 release (see details at the end). I think the script and its comments speaks for itself, but the outcome is certainly not wanted.
for (n in 58950:58970) { cat("n=", n, "\n", sep=""); # Clean up first rm(names, x, y); gc(); # Create a named vector of length n # Try with format "%5d" and it works names <- sprintf("%05d", 1:n); x <- seq(along=names); names(x) <- names; # Extract the first k elements k <- 36422; t0 <- system.time({ y <- x[names[1:k]]; }) str(y); # But with one more it takes # for ever when n >= 58960 k <- k + 1; t1 <- system.time({ y <- x[names[1:k]]; }) # ...then t1/t0 ~= 300-500 and growing! print(t1/t0); str(y); } The interesting this is that if you replace y <- x[names[1:k]]; with idxs <- match(names[1:k], names(x)); y <- x[idxs]; everything is fine. (For those working with the Affy 100K SNP chips, the freaky thing is that the problem occurs at n = 58960 which is exactly the number of SNPs on the Xba array; that's how I found out about the bug/feature it the first place). Tried this on two different systems: > sessionInfo() R version 2.4.0 (2006-10-03) i386-pc-mingw32 locale: LC_COLLATE=English_United States.1252;LC_CTYPE=English_United States.1252;LC_MONETARY=English_United States.1252;LC_NUMERIC=C;LC_TIME=English_United States.1252 attached base packages: [1] "methods" "stats" "graphics" "grDevices" "utils" "datasets" [7] "base" > sessionInfo() R version 2.4.0 (2006-10-03) x86_64-unknown-linux-gnu locale: C attached base packages: [1] "methods" "stats" "graphics" "grDevices" "utils" "datasets" [7] "base" Cheers /Henrik ______________________________________________ R-devel@r-project.org mailing list https://stat.ethz.ch/mailman/listinfo/r-devel