Hi there, Any update on this? Should I create bugzilla ticket and submit patch? Regards Jan Gorecki
On 20 December 2016 at 01:27, Jan Gorecki <j.gore...@wit.edu.pl> wrote: > Hello, > > colnames seems to be not optimized well for data.frame. It escapes > processing for data.frame in > > if (is.data.frame(x) && do.NULL) > return(names(x)) > > but only when do.NULL true. This makes huge difference when do.NULL > false. Minimal edit to `colnames`: > > if (is.data.frame(x)) { > nm <- names(x) > if (do.NULL || !is.null(nm)) > return(nm) > else > return(paste0(prefix, seq_along(x))) > } > > Script and timings: > > N=1e7; K=100 > set.seed(1) > DF <- data.frame( > id1 = sample(sprintf("id%03d",1:K), N, TRUE), # large groups (char) > id2 = sample(sprintf("id%03d",1:K), N, TRUE), # large groups (char) > id3 = sample(sprintf("id%010d",1:(N/K)), N, TRUE), # small groups (char) > id4 = sample(K, N, TRUE), # large groups (int) > id5 = sample(K, N, TRUE), # large groups (int) > id6 = sample(N/K, N, TRUE), # small groups (int) > v1 = sample(5, N, TRUE), # int in range [1,5] > v2 = sample(5, N, TRUE), # int in range [1,5] > v3 = sample(round(runif(100,max=100),4), N, TRUE) # numeric e.g. 23.5749 > ) > cat("GB =", round(sum(gc()[,2])/1024, 3), "\n") > #GB = 0.397 > colnames(DF) = NULL > system.time(nm1<-colnames(DF, FALSE)) > # user system elapsed > # 22.158 0.299 22.498 > print(nm1) > #[1] "col1" "col2" "col3" "col4" "col5" "col6" "col7" "col8" "col9" > > ### restart R > > colnames <- function (x, do.NULL = TRUE, prefix = "col") > { > if (is.data.frame(x)) { > nm <- names(x) > if (do.NULL || !is.null(nm)) > return(nm) > else > return(paste0(prefix, seq_along(x))) > } > dn <- dimnames(x) > if (!is.null(dn[[2L]])) > dn[[2L]] > else { > nc <- NCOL(x) > if (do.NULL) > NULL > else if (nc > 0L) > paste0(prefix, seq_len(nc)) > else character() > } > } > N=1e7; K=100 > set.seed(1) > DF <- data.frame( > id1 = sample(sprintf("id%03d",1:K), N, TRUE), # large groups (char) > id2 = sample(sprintf("id%03d",1:K), N, TRUE), # large groups (char) > id3 = sample(sprintf("id%010d",1:(N/K)), N, TRUE), # small groups (char) > id4 = sample(K, N, TRUE), # large groups (int) > id5 = sample(K, N, TRUE), # large groups (int) > id6 = sample(N/K, N, TRUE), # small groups (int) > v1 = sample(5, N, TRUE), # int in range [1,5] > v2 = sample(5, N, TRUE), # int in range [1,5] > v3 = sample(round(runif(100,max=100),4), N, TRUE) # numeric e.g. 23.5749 > ) > cat("GB =", round(sum(gc()[,2])/1024, 3), "\n") > #GB = 0.397 > colnames(DF) = NULL > system.time(nm1<-colnames(DF, FALSE)) > # user system elapsed > # 0.001 0.000 0.000 > print(nm1) > #[1] "col1" "col2" "col3" "col4" "col5" "col6" "col7" "col8" "col9" > > sessionInfo() > #R Under development (unstable) (2016-12-19 r71815) > #Platform: x86_64-pc-linux-gnu (64-bit) > #Running under: Debian GNU/Linux stretch/sid > # > #locale: > # [1] LC_CTYPE=en_US.UTF-8 LC_NUMERIC=C > # [3] LC_TIME=en_US.UTF-8 LC_COLLATE=en_US.UTF-8 > # [5] LC_MONETARY=en_US.UTF-8 LC_MESSAGES=en_US.UTF-8 > # [7] LC_PAPER=en_US.UTF-8 LC_NAME=C > # [9] LC_ADDRESS=C LC_TELEPHONE=C > #[11] LC_MEASUREMENT=en_US.UTF-8 LC_IDENTIFICATION=C > # > #attached base packages: > #[1] stats graphics grDevices utils datasets methods base # > # > #loaded via a namespace (and not attached): > #[1] compiler_3.4.0 ______________________________________________ R-devel@r-project.org mailing list https://stat.ethz.ch/mailman/listinfo/r-devel