Without a return value in R

Functions

With a return value
Without a return value
Multiple return values
Without parameters
Array of parameters
Out parameters
In-out parameters
Modifying parameters
Optional parameter values
Recursion

add_3_and_print <- function(value) {
cat(value + 3, "\n")
}

# No void: the result is NULL
result <- add_3_and_print(5)
# prints 8
no_value <- is.null(result)
# no_value = TRUE

cat("no_value =", no_value, "\n")