On Tue, Jun 20, 2006 at 09:09:16AM +0800, zhijie zhang wrote: > suppose i want to do the following caulation for 100 times, how to put the > results of x , y and z into the same dataframe/dataset? > x<-runif(1) > y<-x+1 > z<-x+y
Several possibilities: 1) Use rbind Before loop: d = NULL And in the loop: d = rbind(d, data.frame(x, y, z)) 2) Build empty data frame of desired size beforehand and fill by row E.g. for 10 rows: d = data.frame( x=rep(0, 10), y=rep(0,10), z=rep(0,10)) And in the loop (index i): d[i, ] = c(x, y, z) 3) Build vectors first, dataframe after the loop x = NULL y = NULL z = NULL in the loop: x = append(x, runif(1)) ... After loop: d = data.frame(x, y, z) Solutions 1&3 are slower but you don't need to know the final number of rows in advance. Solution 2 is cleaner, in my opinion, but requires that you know the final size. Of course, for the particular example calculation you don't need a loop at all: x = runif(100) y = x+1 z = x+y d = data.frame(x,y,z) cu Philipp -- Dr. Philipp Pagel Tel. +49-8161-71 2131 Dept. of Genome Oriented Bioinformatics Fax. +49-8161-71 2186 Technical University of Munich Science Center Weihenstephan 85350 Freising, Germany and Institute for Bioinformatics / MIPS Tel. +49-89-3187 3675 GSF - National Research Center Fax. +49-89-3187 3585 for Environment and Health Ingolstädter Landstrasse 1 85764 Neuherberg, Germany http://mips.gsf.de/staff/pagel ______________________________________________ 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