On Sat, Jul 26, 2008 at 9:35 AM, Peter Dalgaard <[EMAIL PROTECTED]> wrote: > Henrique Dallazuanna wrote: >> >> Try this: >> >> x <- data.frame(A=c(10,20), B = c("a", "b"), C = c(20,30)) >> x[sapply(x, is.numeric)] >> >> > > Yes, and read ?Extract to clear up the confusion between data$vol and > data[257] and data[[257]] (Section on "Recursive (list-like) objects:"). > Also, ?Extract.data.frame.
...and read up how you can use argument 'colClasses' in read.table() to read/skip selected columns from a tabular data file. Is that how you get your data.frame in the first place?! /Henrik > >> On Sat, Jul 26, 2008 at 11:19 AM, Markus Mühlbacher <[EMAIL PROTECTED]> >> wrote: >> >>> >>> Hello, >>> >>> My question sounds simple, but as I am desperatly searchin for a solution >>> I am >>> asking you all. :) >>> >>> I try to filter out all non-numeric columns of a data frame using a for >>> loop >>> to go through all columns. My if clause looks like this: >>> >>> for(j in 1:length(data)) { >>> >>> ... >>> if(!is.numeric(data[j])) skip <- "not numeric") >>> ... >>> } >>> >>> When I do: is.numeric(data$vol) i get TRUE as result: >>> unfortunately this is not applicable in a for loop, because i need to go >>> through all of the columns using j. >>> I also tried to paste data$ and the name of the column , but this is >>> always a >>> character. >>> >>> When I do: is.numeric(data[257]) i get FALSE as result >>> (257 is the corresponding column index to "vol") >>> >> > > > -- > O__ ---- Peter Dalgaard Øster Farimagsgade 5, Entr.B > c/ /'_ --- Dept. of Biostatistics PO Box 2099, 1014 Cph. K > (*) \(*) -- University of Copenhagen Denmark Ph: (+45) 35327918 > ~~~~~~~~~~ - ([EMAIL PROTECTED]) FAX: (+45) 35327907 > > ______________________________________________ > 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.