R Error in x$ed : $ operator is invalid for atomic vectors

Question

Here is my code:

x<-c(1,2) x names(x)<- c("bob","ed") x$ed 

Why do I get the following error?

Error in x$ed : $ operator is invalid for atomic vectors

Answer 1

From the help file about $ (See ?"$") you can read:

$ is only valid for recursive objects, and is only discussed in the section below on recursive objects.

Now, let's check whether x is recursive

> is.recursive(x) [1] FALSE 

A recursive object has a list-like structure. A vector is not recursive, it is an atomic object instead, let's check

> is.atomic(x) [1] TRUE 

Therefore you get an error when applying $ to a vector (non-recursive object), use [ instead:

> x["ed"] ed   2  

You can also use getElement

> getElement(x, "ed") [1] 2 

Answer 2

The reason you are getting this error is that you have a vector.

If you want to use the $ operator, you simply need to convert it to a data.frame. But since you only have one row in this particular case, you would also need to transpose it; otherwise bob and ed will become your row names instead of your column names which is what I think you want.

x <- c(1, 2) x names(x) <- c("bob", "ed") x <- as.data.frame(t(x)) x$ed [1] 2