How to delete rows where all the columns are zero

Question

I have the following data frame

dat <- data.frame(a = c(0,0,2,3), b= c(1,0,0,0), c=c(0,0,1,3))

Which prints:

> dat 
         


        

Answer 1

Why use sum? it is much more efficient to simply check if all elements are zero. I would do

dat = dat[!apply(dat, 1, function(x) all(x == 0)), ]

If you need to keep track of which rows were removed:

indremoved = which(apply(dat, 1, function(x) all(x == 0)) )
dat = dat[ -indremoved, ]