On Wed, 2006-10-04 at 17:04 +0100, Gavin Simpson wrote: > On Wed, 2006-10-04 at 11:33 -0400, Weiwei Shi wrote: > > Hi, > > > > I use "apply" > > apply(x, 2, factor) > > > > but it does not work. please help. thanks. > >
Ah, lesson one: read the email clearly before replying - just like my old Geography teacher used to tell me! This works dat <- sample(LETTERS, 100, replace = TRUE) # use a data. frame not a matrix dat <- data.frame(matrix(dat, ncol = 10)) dat lapply(dat, factor) # as a list # or, as a data.frame data.frame(lapply(dat, factor)) G > > In what sense does it not work? And how can you possibly expect anyone > on this list to help you as you neither supply the error message you > received nor provide us with x or a reproducible example, nor tell us > what you want to achieve. > > E.g. > > dat <- sample(LETTERS, 100, replace = TRUE) > dat <- matrix(dat, ncol = 10) > dat > apply(dat, 2, factor) > > which appears to be converting a character vector into a factor, which > is then coerced to a numeric vector (as there are only numeric and > character matrices in R) - but I may be wrong: > > as.numeric(factor(dat[,1])) > [1] 7 7 2 5 8 1 4 7 3 6 > > which is the first column of the object returned by apply(dat, 2, > factor). Is this not what you wanted? > > So perhaps you could provide the list with some further information as > you are asked to in the posting guide! > > HTH > > G -- %~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~% Gavin Simpson [t] +44 (0)20 7679 0522 ECRC & ENSIS, UCL Geography, [f] +44 (0)20 7679 0565 Pearson Building, [e] gavin.simpsonATNOSPAMucl.ac.uk Gower Street, London [w] http://www.ucl.ac.uk/~ucfagls/ UK. WC1E 6BT. [w] http://www.freshwaters.org.uk %~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~% ______________________________________________ R-help@stat.math.ethz.ch 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.