# Chapter 7 Lists

Lists arrange elements in a collection of vectors or other data structures. In other words, lists are just a collection of variables, that have no constraints on what types of variables can be included.

Emma <- list(age = 26,
siblings = TRUE,
parents = c("Mike", "Donna")
)

Here, R has created a list variable called Emma, which contains three different variables - age, siblings, and parents. Lets have a look at how R stores this list:

print(Emma)
## $age ## [1] 26 ## ##$siblings
## [1] TRUE
##
## $parents ## [1] "Mike" "Donna" If you wanted to extract one element of the list, you would use the $ operator:

Emma$age ## [1] 26 You can also add new entries to the list, again using the $. For example:

Emma$handedness <- "right" print(Emma) ##$age
## [1] 26
##
## $siblings ## [1] TRUE ## ##$parents
## [1] "Mike"  "Donna"
##
## \$handedness
## [1] "right"