R Return Value from Function
In this article, you’ll learn to return a value from a function in R. You’ll also learn to use functions without the return function.
Many a times, we will require our functions to do some processing and return back the result. This is accomplished with the return()
function in R.
Syntax of return()
return(expression)
The value returned from a function can be any valid object.
Example: return()
Let us look at an example which will return whether a given number is positive, negative or zero.
check < function(x) {
if (x > 0) {
result < "Positive"
}
else if (x < 0) {
result < "Negative"
}
else {
result < "Zero"
}
return(result)
}
Here, are some sample runs.
> check(1) [1] "Positive" > check(10) [1] "Negative" > check(0) [1] "Zero"
Functions without return()
If there are no explicit returns from a function, the value of the last evaluated expression is returned automatically in R.
For example, the following is equivalent to the above function.
check < function(x) {
if (x > 0) {
result < "Positive"
}
else if (x < 0) {
result < "Negative"
}
else {
result < "Zero"
}
result
}
We generally use explicit return()
functions to return a value immediately from a function.
If it is not the last statement of the function, it will prematurely end the function bringing the control to the place from which it was called.
check < function(x) {
if (x>0) {
return("Positive")
}
else if (x<0) {
return("Negative")
}
else {
return("Zero")
}
}
In the above example, if x > 0
, the function immediately returns "Positive"
without evaluating rest of the body.
Multiple Returns
The return()
function can return only a single object. If we want to return multiple values in R, we can use a list (or other objects) and return it.
Following is an example.
multi_return < function() {
my_list < list("color" = "red", "size" = 20, "shape" = "round")
return(my_list)
}
Here, we create a list my_list
with multiple elements and return this single list.
> a < multi_return() > a$color [1] "red" > a$size [1] 20 > a$shape [1] "round"
Check out these examples to learn more:

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