Hello, Because x[] keeps the dimensions, unlike just x.
Hope this helps, Rui Barradas Em 06-12-2012 16:24, Juliet Hannah escreveu:
All, Can someone describe what x[] <- lapply(x, as.numeric) I see that it is putting the list elements into a data frame. The results for lapply are a list, so how does this become a data frame. Thanks, Juliet On Mon, Dec 3, 2012 at 5:49 PM, Fisher Dennis <fis...@plessthan.com> wrote:Colleagues, This past week, I asked the following question: I have a file that looks that this: TABLE NO. 1 PTID TIME AMT FORM PERIOD IPRED CWRES EVID CP PRED RES WRES 2.0010E+03 3.9375E-01 5.0000E+03 2.0000E+00 0.0000E+00 0.0000E+00 0.0000E+00 1.0000E+00 0.0000E+00 0.0000E+00 0.0000E+00 0.0000E+00 2.0010E+03 8.9583E-01 5.0000E+03 2.0000E+00 0.0000E+00 3.3389E+00 0.0000E+00 1.0000E+00 0.0000E+00 3.5321E+00 0.0000E+00 0.0000E+00 2.0010E+03 1.4583E+00 5.0000E+03 2.0000E+00 0.0000E+00 5.8164E+00 0.0000E+00 1.0000E+00 0.0000E+00 5.9300E+00 0.0000E+00 0.0000E+00 2.0010E+03 1.9167E+00 5.0000E+03 2.0000E+00 0.0000E+00 8.3633E+00 0.0000E+00 1.0000E+00 0.0000E+00 8.7011E+00 0.0000E+00 0.0000E+00 2.0010E+03 2.4167E+00 5.0000E+03 2.0000E+00 0.0000E+00 1.0092E+01 0.0000E+00 1.0000E+00 0.0000E+00 1.0324E+01 0.0000E+00 0.0000E+00 2.0010E+03 2.9375E+00 5.0000E+03 2.0000E+00 0.0000E+00 1.1490E+01 0.0000E+00 1.0000E+00 0.0000E+00 1.1688E+01 0.0000E+00 0.0000E+00 2.0010E+03 3.4167E+00 5.0000E+03 2.0000E+00 0.0000E+00 1.2940E+01 0.0000E+00 1.0000E+00 0.0000E+00 1.3236E+01 0.0000E+00 0.0000E+00 2.0010E+03 4.4583E+00 5.0000E+03 2.0000E+00 0.0000E+00 1.1267E+01 0.0000E+00 1.0000E+00 0.0000E+00 1.1324E+01 0.0000E+00 0.0000E+00 The file is reasonably large (> 10^6 lines) and the two line header is repeated periodically in the file. I need to read this file in as a data frame. Note that the number of columns, the column headers, and the number of replicates of the headers are not known in advance. I received a number of replies, many of them quite useful. Of these, one beat out all the others in my benchmarking using files ranging from 10^5 to 10^6 lines. That version, provided by Jim Holtman, was: x <- read.table(FILE, as.is = TRUE, skip=1, fill=TRUE, header = TRUE) x[] <- lapply(x, as.numeric) x <- x[!is.na(x[,1]), ] Other versions involved readLines, following by edits, following by cat (or write) to a temp file, then read.table again. The overhead with invoking readLines, write/cat, and read.table was substantially larger than the strategy of read.table / as.numeric / indexing Thanks for the input from many folks. Dennis Dennis Fisher MD P < (The "P Less Than" Company) Phone: 1-866-PLessThan (1-866-753-7784) Fax: 1-866-PLessThan (1-866-753-7784) www.PLessThan.com ______________________________________________ R-help@r-project.org mailing list https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide http://www.R-project.org/posting-guide.html and provide commented, minimal, self-contained, reproducible code.______________________________________________ R-help@r-project.org mailing list https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide http://www.R-project.org/posting-guide.html and provide commented, minimal, self-contained, reproducible code.
______________________________________________ R-help@r-project.org mailing list https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide http://www.R-project.org/posting-guide.html and provide commented, minimal, self-contained, reproducible code.
