A variable is used to store data that can be accessed later by subsequent code. In R, there are no variable “declaration” commands. Instead, they are created with the assignment operator,
<- (The more familiar assignment operator,
=, can be used instead, but is discouraged).
# This creates a variable containing the string "value"variable <- "value"
The assignment operator can be chained together to initialize multiple variables at once:
var1 <- var2 <- var3 <- 0
In R, writing a defined variable name by itself on a line has the effect of printing its associated value:
score <- 100# This line:score # Output 100# Has the same effect as this line:print(score) # Output 100
R variables must adhere to the following naming conventions:
- The name can be a combination of letters, digits, period(.) and underscore(_).
- It must start with a letter or a period.
- If it starts with a period, the second character cannot be a number.
- It cannot start with a number or an underscore.
- Variable names are case-sensitive.
- Reserved words (
The following code snippet shows examples of valid variable names in R:
foo <- 1Foo <- 2 # A different variable from "foo" above.bar <- TRUEfoo_bar <- "value"3.5 -> Foo123.4 # Rightward assignment.