na.strings applied to a dataframe

Question

I currently have a dataframe in which there are several rows I would like converted to \"NA\". When I first imported this dataframe from a .csv, I could use na.strings=c(\"A

Answer 1

Since we don't have your data I will use mtcars. Suppose we want to set values anywhere in mtcars that are equal to 4 or 19.2 to NA

ind <- which(mtcars == 4, arr.ind = TRUE)
mtcars[ind] <- NA

In your setting you would replace this number by "D" or "E"