R: Selecting unique values out of dataset

Many a times you have a dataset or a column which has a range of values and you wish to know the domain or range of values the column assumes. To do so run the following command:

>  y<-c('A', 'A','A','A','B', 'B','B','B','B','B','B','B','B', 'C','C','D','D', 'E','E', 'E','E','E' ,'E','E','E' ,'E','F','F','F', 'F','F', 'F','F', 'F','F')
> levels(factor(y))
[1] "A" "B" "C" "D" "E" "F"
> unique(y)
[1] "A" "B" "C" "D" "E" "F"