For illustration, I will show you a slightly more complex example for the usage of return in R. Consider the following function:. If we apply the function, we get the following list output:. The more complex our function gets, the more helpful is the return command. We could simply go back to our function and search for return to get a quick overview of our output. Therefore, I recommend to use return in every user-defined function. Do you want to learn more about user-defined functions in R?
Please accept YouTube cookies to play this video. By accepting you will be accessing content from YouTube, a service provided by an external third party. YouTube privacy policy. Accept YouTube Content. As a final note: In this tutorial we have returned a single value from our user-defined function. We can create user-defined functions in R. They are specific to what a user wants and once created they can be used like the built-in functions. Below is an example of how a function is created and used.
The arguments to a function call can be supplied in the same sequence as defined in the function or they can be supplied in a different sequence but assigned to the names of the arguments. We can define the value of the arguments in the function definition and call the function without supplying any argument to get the default result.
But we can also call such functions by supplying new values of the argument and get non default result. Arguments to functions are evaluated lazily, which means so they are evaluated only when needed by the function body. Nishant Malik. Asif Hussain. R - Functions Advertisements. Previous Page. The argument As an example, in the function,.
By default, the R functions will return the last evaluated object inside it. You can also make use of the return function, which is especially important when you want to return one object or another, depending on certain conditions, or when you want to execute some code after the object you want to return.
It is worth to mention that you can return all types of R objects, but only one. For that reason it is very usual to return a list of objects, as follows:. When you run the function, you will have the following output. Recall to have the sn and an functions loaded in the workspace. You may have noticed that in the previous case it is equivalent to use the return function or not using it. However, consider the following example, where we want to check whether the parameters passed to the arguments are numbers or not.
For this, if any of the parameters is not a number we will return a string, but if they are numbers the code will continue executing. If we have used the print function instead of return , when some parameter is not numeric, the text will be returned but also an error, since all the code will be executed.
In R it is not necessary to declare the variables used within a function.
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