How to write a recursive function in R?

Recipe Objective

Recursion is a type of looping mechanism which exploits the working of functions in R. In R, recursion occurs when the function calls itself which results in a formation of loop. ​

Functions which uses the concept of rescursion to perform iterative tasks are known as Recursive functions.

Loops are an important feature in R-language but it increases the memory requirements of a program. Thus, recursive function is a better alternative than using a loop in many cases as it frees up memory used after every iteration. ​

In this recipe, we will learn how to write a recursive function in R by using an example of factorial using recursion in R. ​

Example: Factorial using Resursive function in R

Factorial of a number is calculated by the given formula: n! = (n)(n-1)(n-2)(n-3)....1

Steps to be followed:

1. Creation of a recursive function using if..else statement
2. Calling the function and getting an output

# 1. creation of a recursive function rec_func_factorial = function(n){ if (n == 0 || n == 1){ return (1) } else { return(n*rec_func_factorial(n-1)) } } # 2. calling the function #calculating the factorial of 3 rec_func_factorial(3)

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