R for Data Science Cookbook

Understanding closure

Functions are the first-class citizens of R. In other words, you can pass a function as the input to an other function. In previous recipes, we illustrated how to create a named function. However, we can also create a function without a name, known as closure (that is, an anonymous function). In this recipe, we will show you how to use closure in a standard function.

Getting ready

Ensure that you completed the previous recipes by installing R on your operating system.

How to do it...

Perform the following steps to create a closure in function:

1. First, let's review how a named function works:

   >addnum<- function(a,b){
   + a + b
   + }
   >addnum(2,3)
   [1] 5
   

2. Now, let's perform the same task to sum up two variables with closure:

   > (function(a,b){ ...