A list in R is simply a collection of ordered and changeable data. A list contains different data types such as strings or numbers. The elements contained in a given list are referred to as the item of the list.
We use the list() function to create a list in R. This function takes the list of items you want on the list as parameters.
# creating a string and numerical listsmylist1 <- list("cherry", 'banana', 'orange')mylist2 <- list(1, 2, 3, 4, 5)# to print the listsmylist1mylist2
We create two list variables mylist1 and mylist2 that have strings and numbers respectively.
Remember that in R, the first index of any given character is 1. For example, the “H” in “Hello” has the index value 1, the second character “e” has index value 2, and so on.
Now, to add an item to the list in R, we use the append() function. To add an item to the right of a specified index in a code, we add after = index number inside the append function.
append(list, item, after = index number)
# creating a string and numerical listsmylist <- list("cherry", 'banana', 'apple')# implementing the append() functionappend(mylist, "orange", after = 2)
In the code above we create a list mylist, and add the item "orange" to the list right after the second item, “banana”.