?cut This is in `An Introduction to R', the manual which ships with R and basic reading.
On Fri, 26 Aug 2005, David James wrote: > What is the quickest way to create many categorical variables > (factors) from continuous variables? > > This is the approach that I have used: > > # create sample data > N <- 20 > x <- runif(N,0,1) > > # setup ranges to define categories > x.a <- (x >= 0.0) & (x < 0.4) > x.b <- (x >= 0.4) & (x < 0.5) > x.c <- (x >= 0.5) & (x < 0.6) > x.d <- (x >= 0.6) & (x < 1.0) > > # create factors > i <- runif(N,1,1) > x.new <- (i*1*x.a) + (i*2*x.b) + (i*3*x.c) + (i*4*x.d) > x.factor <- factor(x.new) > > I'm looking for a better / simpler / more elegant / more robust (as > the number of categories increases) way to do this. I also don't > like that my factor names can only be numbers in this example. I > would prefer a solution to take a form like the following (inspired > by the "hist" function): > > # define breakpoints > x.breaks = c(0, 0.4, 0.5, 0.6, 1.0) > x.factornames = c( "0 - 0.4", "0.4 - 0.5", "0.5 - 0.6", "0.6 - 1.0" ) > x.factor = unknown.function( x, x.breaks, x.factornames ) > > Thanks, > David > > P.S. Here's what I have read to try to find the answer to my problem: > * "Introductory Statistics with R" > * "A Brief Guide to R for Beginners in Econometrics" > * "Econometrics in R" -- 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 ______________________________________________ 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