Error: $ Operator is Invalid For Atomic Vectors: How To Fix – Full Guide

The following is an example of a common R error: Error: $ Operator is Invalid For Atomic Vectors

This error occurs when you use the $ operator to access an element of an atomic vector. Any one-dimensional data object created by using R’s c() or vector() functions is referred to as an “atomic vector.”

Unfortunately, the $ cannot be used to access atomic vector elements. You must instead use double brackets [[]] or the getElement() function.

This tutorial provides practical examples of how to deal with this error.

How To Replicate This Error?

Assume we try to use the $ operator in R to access an element in the following vector:

#define vector
x <- c(1, 3, 7, 6, 2)

#provide names
names(x) <- c('a', 'b', 'c', 'd', 'e')

#display vector
x

a b c d e 
1 3 7 6 2

#attempt to access value in 'e'
x$e

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

We get an error because using the $ operator to access elements in atomic vectors is invalid. We can also confirm that our vector is atomic:

#check if vector is atomic
is.atomic(x)

[1] TRUE

How To Fix This Error?

Solution 1:

The [[]] notation can be used to access elements in a vector by name:

#define vector
x <- c(1, 3, 7, 6, 2)

#provide names
names(x) <- c('a', 'b', 'c', 'd', 'e')

#access value for 'e'
x[['e']]

[1] 2

Solution 2:

The getElement() notation can also be used to access elements in a vector by name:

#define vector
x <- c(1, 3, 7, 6, 2)

#provide names
names(x) <- c('a', 'b', 'c', 'd', 'e')

#access value for 'e'
getElement(x, 'e')

[1] 2

Solution 3:

Another method for accessing elements in a vector by name is to first convert the vector to a data frame, then use the $ operator to access the value:

#define vector
x <- c(1, 3, 7, 6, 2)

#provide names
names(x) <- c('a', 'b', 'c', 'd', 'e')

#convert vector to data frame
data_x <- as.data.frame(t(x))

#display data frame
data_x

  a b c d e
1 1 3 7 6 2

#access value for 'e'
data_x$e

[1] 2

Also read:- [Solved] Error In Xy.Coords(X, Y, Xlabel, Ylabel, Log) : ‘X’ And ‘Y’ Lengths Differ

Conclusion

And that was all about this error. In this article, we tried to explain to you the reason behind the occurrence of this error, along with a couple of solutions. We hope you found this article helpful.

If you have any queries, please let us know in the comments below.