Attributes

• Some R functions use attributes to store indices, names or other useful information.

y <- c(10, 20, NA, 40, 50, NA, 70)
(y_na_free <- na.omit(y))

## [1] 10 20 40 50 70
## attr(,"na.action")
## [1] 3 6
## attr(,"class")
## [1] "omit"