The list() function works just like the concatenation function c(). It places each of the elements next to each other, while preserving their original data types and names of the objects. To get access to the component of a list, the simplest way is to use the double-square brackets along with a sequential index number of the element position as follows:

    listA[[1]]

The preceding function will give the output of the first element of the list, which is a character vector of four elements, as follows:

    [1] "Cricket"    "Football"   "Basetball" "Rugby"   

You can use the dollar $ operator next to the name of the list object to extract elements from the list. However, the list object must be a named list; otherwise the $ operator will not work. For example, to extract the data frame from listB, execute the following code snippet:

    listB$data1

    > listB$data1
  ID hourSpetOnInternet GENDER
    1  1                  5      M
    2  2                  3      F
    3  3                  4      F
    4  4                  1      M
    5  5                  2      F