R has gained popularity among data scientists and statisticans in last few years. Popular R packages are developed after rigorous testing and returns error messages with more explanation which is easy for novice R users to understand them. In base R, one of the most common error encountered is ![Fix R Error : $ operator is invalid for atomic vectors]()
$ operator is invalid for atomic vectors. 
Background
This error appears when you try to use an element of an atomic vector using the $ operator. Let's call atomic vector as character/numeric vector which most R programmers are familiar with. There are 2 more types of atomic vectors - logical and integer. Let's understand it via examples. See them below
You can check if a vector is an atomic or not by using
# Numeric Vector
numVec <- c(3, 2.5, 5.6)
# Character Vector
charVec <- c("Hello", "GroupA")
# Integer Vector
intVec <- c(2L, 4L, 11L)
# Logical Vector
logicalVec <- c(TRUE, FALSE, T, F)
is.atomic(numVec). It returns TRUE if it is an atomic vector else FALSE. Let's name the numeric vector using names() function
names(numVec) <- c('A', 'B', 'C')
numVec
A B C
3.0 2.5 5.6
When we try to access first value by using name A using dollar $ operator, it returns this error.
numVec$A
Error in numVec$A : $ operator is invalid for atomic vectors
There are three ways we can fix this error.
Solutions
Solution 1 : Use Double Brackets
We can use double brackets[[ ]] to access element by name from an atomic vector. Make sure to use quotes in the name as it is a string.
numVec[['A']]
[1] 3
Can't we use Single Bracket?
Yes we can use single bracket [ ] for this task but the output will be in a different format. It returns named number instead of just the number. Refer the ouput below. We can remove name like this
numVec['A']
A
3
unname(numVec['A']). Hence it's better to use double brackets as single bracket complicates things unless you want named number. Solution 2 : Use getElement( )
getElement( ) follows this syntax style -getElement(object, name). It was designed for this kind of problem statement only. getElement(numVec, 'A')
[1] 3
Solution 3 : Convert to Dataframe
This is not a recommended solution but the intend is to show you another way to solve this problem usingdata.frame( ). We need to transpose before wrapping the vector in data.frame( ) as we need data to be stored in a single row with name of vector as column names instead of 3 rows.
myDF <- data.frame(t(numVec))
myDF$A
[1] 3