Question

I’m using the following method to sort a data.frame.

# Dummy data
dat <- data.frame(a=letters[1:26],b=runif(26),c=rnorm(26))
# Sort
dat <- dat[with(dat, order(-b)),]

I’d like to be able to generate “-b” using something akin to paste so I can sort programmatically.

Something like:

dat <- dat[with(dat, order(paste("-b"))),]

I’ve tried things like paste(), cat(), get(), getElement(), to no avail.

Answer 1

how about this?

sort.var <- 'b'
inverse <- TRUE
dat <- dat[order(dat[[sort.var]],decreasing=inverse),]