I want to create a function in R, which take data as a function, do some operation on it(add some columns/Rows etc) and return it. I found usually I can not do so.
f <- function(d = cars){
d$new = ifelse(d$dist > rep(10, nrow(d)), 1, 0)
return d
}
Error: unexpected symbol in:
"d$new= ifelse(d$dist>rep(10,nrow(d)),1,0)
return d"
If I remove return d, I get only the vector, not whole data frame.
Any suggestion?
Functions in R return the value from the last statement executed. When you do an assignment, the value from the left side of the assignment is the (invisibly) returned result. For exampel
d <- cars
a <- (d$new <- ifelse(d$dist>10, 1, 0))
a
# [1] 0 0 0 1 1 0 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1
# [40] 1 1 1 1 1 1 1 1 1 1 1
So in your example you're merely returning the vector you just created. R doesn't know that you want to return the whole d
data.frame. If you put the return(d)
, it will know that's what you want. You can even just put d
on the last line by itself to return that value.
Collected from the Internet
Please contact [email protected] to delete if infringement.
Comments