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.
