Is Starred Functions In R

R Programming

In R, the concept of “starred” functions may not be as widely known as other language features, but they can be incredibly useful under the right circumstances. Starred functions, also known as “splat” or “ellipsis” functions, allow for the passing of an arbitrary number of arguments to a function. This unconventional yet powerful feature can be a game-changer in certain programming scenarios.

Understanding the Starred Functions

When defining a function in R, you typically specify a fixed number of arguments that the function can accept. However, there are situations where you may want to pass an unspecified number of arguments to a function. This is where the starred functions come into play. By using an ellipsis (…) as an argument in the function definition, you can indicate that the function can accept any number of additional arguments.

For example, let’s say I have a function called sum_values that I want to be able to handle an arbitrary number of numeric inputs. I can define the function as follows:

sum_values <- function(...){ result <- sum(...) return(result) }

Using Starred Functions in Practice

One practical application of starred functions is when you are working with functions that pass their arguments along to other functions. This is commonly seen in wrapper functions where you may want to modify or augment the arguments before passing them to an underlying function. By using starred functions, you can capture all the incoming arguments without needing to explicitly define them in the function signature.

Another common use case for starred functions is in custom plotting functions or data manipulation functions where you may not know in advance how many arguments users will need to pass. The flexibility of the ellipsis allows for a dynamic and adaptable approach to handling various input scenarios.

Personal Experience with Starred Functions

As a data scientist, I have found starred functions to be invaluable in my R programming journey. There have been numerous occasions where I needed to create functions that could accommodate varying inputs without imposing strict constraints on the user. By leveraging the power of star functions, I was able to streamline my code and create more versatile and user-friendly functions.


Starred functions in R offer a unique and powerful way to handle variable numbers of arguments in function definitions. While they may not be needed in every R programming task, they can be a critical tool in certain scenarios, especially when building flexible, adaptable, and user-friendly functions. Embracing the ellipsis in function definitions can open up new possibilities and simplify the handling of diverse input scenarios.