Page 42 - Applied Statistics with R

42 CHAPTER 3. DATA AND PROGRAMMING

• ex_list[[1]] returns the first element of the list, in this case, a vector.

# subsetting
ex_list$e

## [,1] [,2] [,3] [,4] [,5]
## [1,] 1 0 0 0 0
## [2,] 0 1 0 0 0
## [3,] 0 0 1 0 0
## [4,] 0 0 0 1 0
## [5,] 0 0 0 0 1

ex_list[1:2]

## $a
## [1] 1 2 3 4
##
## $b
## [1] TRUE

ex_list[1]

## $a
## [1] 1 2 3 4

ex_list[[1]]

## [1] 1 2 3 4

ex_list[c("e", "a")]

## $e
## [,1] [,2] [,3] [,4] [,5]
## [1,] 1 0 0 0 0
## [2,] 0 1 0 0 0
## [3,] 0 0 1 0 0
## [4,] 0 0 0 1 0
## [5,] 0 0 0 0 1
##
## $a
## [1] 1 2 3 4