On Mon, 15 May 2006, Satoshi Takahama wrote: > Hello everyone, > > If I want to convert or combine a (large) character matrix into a data > frame without having any of its columns convert into a factor class, > is there a simple solution? I() says it will operate on 'an > object' but it seems that unless the object is a vector, the results > are not what I expect. > > For instance, if g is a 2x2 character matrix, as.data.frame(I(g)) will > return an object of the data frame class but not structured in the way > I intended.
Which is? Your subject line says you want to retain a character matrix, and that is exactly what happens: > g <- matrix(letters[1:4], 2, 2) > as.data.frame(I(g)) x.1 x.2 1 a c 2 b d > What I hope to retrieve is the result of > > h = data.frame(I(g[,1]),I(g[,2])) > names(h) = dimnames(g)[[2]] So it seems you don't actually want to `retain character matrices'. > With data sets of 100+ columns, wrapping I() around each column can be > very time-consuming when invoking the functions data.frame(), cbind(), > or as.data.frame(). Really? How are you trying to do it? > R used to offer the optional argument, as.is=TRUE > (and S-PLUS offered stringsAsFactors=FALSE), to accomplish what this > task but it seems that this argument was removed some time ago. It was not there in R 1.0.0, so you are talking about alpha/beta versions. I think it existed only when data.frame was a rather different class. > Is there a more attractive alternative available now? I guess what you want is for each column of a character matrix to be inserted as a character vector. There are several ways: a simple one is DF <- data.frame(g) for(i in 1:ncol(g)) DF[[i]] <- g[, i] -- Brian D. Ripley, [EMAIL PROTECTED] Professor of Applied Statistics, http://www.stats.ox.ac.uk/~ripley/ University of Oxford, Tel: +44 1865 272861 (self) 1 South Parks Road, +44 1865 272866 (PA) Oxford OX1 3TG, UK Fax: +44 1865 272595 ______________________________________________ [email protected] mailing list https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide! http://www.R-project.org/posting-guide.html
