R Returning Values
return() hands a value back to the caller and ends the function call at once.
An early return
This function returns adult when the age reaches 18. A younger age returns minor instead.
check_age <- function(age) {
if (age >= 18) {
return("adult")
}
return("minor")
}
print(check_age(20))
print(check_age(12))Two styles, one answer
One function gives back its last value and the other uses return. Both calls with 5 give back 25.
square_a <- function(num) {
num * num
}
square_b <- function(num) {
return(num * num)
}
print(square_a(5))
print(square_b(5))Storing a returned value
The call gives back half of 10. The returned value is stored in result and then printed.
half <- function(num) {
return(num / 2)
}
result <- half(10)
print(result)Example
square <- function(num) {
return(num * num)
}
print(square(3) + 1)Key points
- return() gives its value to the caller as the result of the call.
- The call ends as soon as return() runs.
- Lines after a return() that runs do not run in that call.
- A block can also give back its last value with no return() at all.
- The two styles can give back the same result.
- A returned value can sit inside a bigger expression.
In this example, square gives back 9 for the input 3. The returned 9 is then used inside the bigger expression and 1 is added before printing.
Try it Yourself
Edit the code, then press Run.
Running is simulated · rdrr.io R Snippets
Exercise
What does return() do when it runs inside a function?