Lexical scope

Lexical scoping is a convention used by many languages that determine when an object is available by its name. When you run the code below you will see which x is available at different points in the code.

x <- 8
my_func <- function(y){
    x <- 9
    print(x)
    y + x
}
my_func(x)
print(x)

Note that when we define x as 9, this is inside the function, but it is 8 after you run the function. The x changed inside the function but not outside.

After running the code below, what is the value of x?

x <- 3
my_func <- function(y){
    x <- 5
    y
    print(x)
}
my_func(x)

Exercise

Lexical scope

Instructions