Question

How can I define Global Variables in R

Answer 1

The variables declared inside a function are local to that function.
For e.g.:

foo <- function() {
    m <- 2
}
foo()
m    //gives the following error: Error: object 'bar' not found.

If you want to make m a global variable, you should do:

foo <- function() {
    m <<- 2
}
foo()
m //In this case m is accessible from outside the function.