1.7 Hello World
To print an output, simply use the function print()
##  "Hello Word!"
Sometimes we would also want to display the value of a variable:
x <- 4 y <- 5 z <- x + y print(z)
##  9
However, we want to print the description of the variable too. Then we have to use function cat() to combine description and output.
x <- 4 y <- 5 cat('The sum of x and y is', x+y)
## The sum of x and y is 9