You can use the is.null function in R to test whether a data object is NULL.
This function uses the following basic syntax:
is.null(x)
where:
- x: An R object to be tested
The following examples show how to use this function in different scenarios.
Example 1: Use is.null to Check if Object is NULL
The following code shows how to use is.null to test whether two different vectors are equal to NULL:
#create non-null vector x #test if x is NULL is.null(x) [1] FALSE #create null vector y #test if y is NULL is.null(y) [1] TRUE
The is.null function returns FALSE for the first vector and TRUE for the second vector.
Also note that is.null will return TRUE if a vector exists but is empty:
#create empty vector x #test if x is NULL is.null(x) [1] TRUE
Example 2: Use !is.null to Check if Object is Not NULL
The following code shows how to use !is.null to test whether two different vectors are not equal to NULL:
#create non-null vector x #test if x is not NULL !is.null(x) [1] TRUE #create non-null vector y #test if y is not NULL !is.null(y) [1] FALSE
The !is.null function returns TRUE for the first vector and FALSEÂ for the second vector.
Additional Resources
The following tutorials explain how to perform other common operations with missing values in R:
How to Use is.na in R
How to Use na.rm in R
How to Use na.omit in R