You don't need to find out the column index. This works: Df[5,'bat'] <- 100
-Don At 5:01 PM -0400 8/2/06, John Kane wrote: >Simple problem but I don't see the answer. I'm trying >to clean up some data >I have 120 columns in a data.frame. I have one value >in a column named "blaw" that I want to change. How do >I find the coordinates. I can find the row by doing a >subset on the data.frame but how do I find out here >"blaw " is in columns without manually counting them >or converting names(Df) to a list and reading down the >list. > >Simple example > >cat <- c( 3,5,6,8,0) >dog <- c(3,5,3,6, 0) >rat <- c (5, 5, 4, 9, 0) >bat <- c( 12, 42, 45, 32, 54) > >Df <- data.frame(cbind(cat, dog, rat, bat)) >Df >subset(Df, bat >= 50) > >----results > cat dog rat bat >5 0 0 0 54 > > >Thus I know that my target is in row 5 but how do I >figure out where 'bat' is? > >All I want to do is be able to say >Df[5,4] <- 100 > >Is there some way to have function(bat) return the >column number: some kind of a colnum() function? I >had thought that I had found somthing in >library(gdata) matchcols but no luck. > >______________________________________________ >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. -- -------------------------------------- Don MacQueen Environmental Protection Department Lawrence Livermore National Laboratory Livermore, CA, USA ______________________________________________ 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.