R Recursion

Recursion in R is like a mirror reflecting a mirror—it's a function that calls itself to solve a problem, breaking it down into smaller, simpler instances until it reaches a base case where it doesn't need to call itself anymore.

Let's explain this with an example of a factorial function, which calculates the factorial of a non-negative integer:

Here's what's happening:

• The factorial function takes an integer n as input.
• Inside the function, there's a conditional statement (if) to check if n is equal to 0. If it is, the function returns 1 because the factorial of 0 is defined as 1 (this is the base case).
• If n is not 0, the function calculates the factorial recursively by multiplying n with the factorial of n - 1. This is the recursive case.
• The function keeps calling itself with decreasing values of n until it reaches the base case, where n equals 0.
• Once the base case is reached, the function starts returning values back up the chain of recursive calls, computing the factorial of each intermediate value of n.
• Finally, the result is returned to the caller.

Recursion can be a powerful tool for solving problems that can be broken down into smaller, similar sub-problems. However, it's important to ensure that there's a base case to prevent infinite recursion and that the problem can indeed be solved using recursion.