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

Simple English Explanation:

Let’s break this down into the relevant parts. The $ operator is one of R’s default methods, generally used to access the individual elements of data frame or list. For the sake of this article, the R language considers lists to be an recursive object – one which can be accessed through recursive programming methods. You have most likely attempted to apply the $ operator to a different data structure.

And as you can see, the R language doesn’t particularly like this turn of events, thus our lovely error message:

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

When Do We See This? What Are Atomic Vectors?

You have most likely attempted to apply the $ operator to access an element of a vector (aka an array or string in other languages). These are referred to as atomic vectors in R. They occupy a continuous space in memory, each cell after the next. So they do not have the same access structure as a list or dictionary.

Individual elements of an atomic vector can be accessed sequentially. For example, position 1, position 2, etc. Notation for this is vect[1], vect[2], vect[3].

You can also express this as a variable, for inclusion in an iterative loop.

How Do I Fix This?

Try converting your $ operator to a bracket reference. You can also use the getElement() function.

> testlist <- c(1,2,3) 
> testlist$s
Error in testlist$s : $ operator is invalid for atomic vectors
> testlist[1]
[1] 1
> getElement(testlist,1)
[1] 1

As you can see, we successfully triggered the error in this example by using the $ operator to attempt to access an atomic vector (our array) improperly. By using brackets or getElement(), we get the desired result.

Note that this error might be buried a level or two down in your code, if there is a particular method or procedure that was fed a type of data it wasn’t expecting to work with. Be ready to dig a little.

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