A very important concept in programming is variable assignment. In R there are several assignment operators available: <-, <<-, =, ->, ->>. For the sake of simplicity we will use the <- assignment operator throughout the tutorial.

Let us assign two numerical values to variables denoted as x and y:

x <- 25
y <- 11

R will not print out anything to the console. However, we now have assigned the value 25 to the variable x and the value 11 to the variable y. These variables are now stored in our interactive workspace, referred to as global environment. The idea of environments, by which a set of names is associated to a set of values is quite fundamental, however, a sound discussion on this topic is beyond the topic of this section. The companion website for Advanced R, a book by Hadley Wickham, offers a nice introduction on this topic (here).

We can ask R which variable are currently stored in our workspace by typing the ls() command.

ls()

## [1] "x" "y"

We can reuse these values by simple using the variable names in our arithmetic calculations.

x

## [1] 25

y

## [1] 11

x + y

## [1] 36

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