CODEWITHSUNDEEP
rfunction
Devang Akotia
Devang Akotia

Reputation: 119

Passing arguments in R within functions, error unused arguments

Consider the first function:

fruits <- function(apples, oranges){
   apples + oranges
}

#example#
> fruits(2,3) 
[1] 5

The second function uses the first function fruits:

fruitsandvegetables <- function(tomatoes){
   fruits(apples, oranges) + tomatoes
}

Now consider the following errors:

> fruitsandvegetables(3)
  Error in fruits(apples, oranges) : object 'apples' not found
> fruitsandvegetables(3, apples = 2, oranges = 3)
  Error in fruitsandvegetables(3, apples = 2, oranges = 3) : 
  unused arguments (apples = 2, oranges = 3)
> fruitsandvegetables(tomatoes = 3, apples = 2, oranges = 3)
  Error in fruitsandvegetables(tomatoes = 3, apples = 2, oranges = 3) : 
  unused arguments (apples = 2, oranges = 3)

I understand these errors, but I was wondering if there is a simple way to get around this. For more complex function with many arguments, rewriting the functions can be very tedious.

In otherwords I would like the function to behave this way:

fruitsandvegetables(3, apples = 2, oranges =3)
[8]

Upvotes: 1

Views: 1270

Answers (2)

Ronak Shah
Ronak Shah

Reputation: 389235

There is no way fruitsandvegetables function comes to know what is apples and oranges.

You may include these two parameters as argument to the function like , 

fruitsandvegetables <- function(tomatoes, apples, oranges) {
     fruits(apples, oranges) + tomatoes 
}

fruitsandvegetables(3, apples = 2,oranges = 3)
#[1] 8

Moreover, 

fruitsandvegetables(3,2,3)
#[1] 8

Upvotes: 0

baptiste
baptiste

Reputation: 77116

try this,

fruitsandvegetables <- function(tomatoes, ...){
  fruits(...) + tomatoes
}

Note: problems may arise if a tomato turns out to be a fruit

Upvotes: 4

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