Selecting variables from a list of data.frames

Ben Bolker · 2009-01-06T14:25:46Z

Magnus zulutime.net> writes: > > I have a simulation program that generates a data frame for each run. I > aggregate the data.frames into a list (df.list). The structure of all data > frames is the same, only the values are different. > > I then want to aggregate the various runs. Currently I use the following > method (for three runs): > > means = (df.list[[1]]$variable + df.list[[2]]$variable + > df.list[[3]]$variable)/3 > > I would like to do this in a more parsimoniou

Ben Bolker

Tue, Jan 6, 2009 6:25 AM

Magnus <account <at> zulutime.net> writes:

x <- sapply(df.list,"[[","variable")  

will extract the variables as a matrix.
If the variables are all vectors of the same
length then you might follow this with
rowSums(x)/ncol(x) or apply(x,1,mean)

Thread (2 messages)

Magnus Selecting variables from a list of data.frames Jan 6 Ben Bolker Selecting variables from a list of data.frames Jan 6