3.8 NULL

Special type of object that:

• Length 0
• Cannot have attributes

typeof(NULL)
#> [1] "NULL"

length(NULL)
#> [1] 0

x <- NULL
attr(x, "y") <- 1
#> Error in attr(x, "y") <- 1: attempt to set an attribute on NULL

is.null(NULL)
#> [1] TRUE