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R Recursion

Recursion in R occurs when a function calls itself. It is a powerful technique used to solve problems that can be broken down into smaller, similar sub-problems. However, care must be taken to ensure the function has a base case to prevent infinite recursion.

Key Topics

Recursion Example

# Example of a recursive function
factorial <- function(n) {
    if (n <= 1) {
        return(1)
    } else {
        return(n * factorial(n - 1))
    }
}

# Calling the recursive function
factorial(5)

Output:

[1] 120

Code Explanation: The factorial function calculates the factorial of n by calling itself with n - 1 until n is less than or equal to 1. The base case n <= 1 stops the recursion and returns 1.

Base Case Importance

A base case is essential in a recursive function to terminate the recursion. Without a base case, the function would continue to call itself indefinitely, leading to a stack overflow error.

Key Takeaways

  • Recursion is useful for problems that can be divided into smaller sub-problems.
  • A base case is necessary to stop the recursive calls and prevent infinite recursion.
  • Recursive functions can be elegant but may be less efficient for deep recursion due to memory limitations.
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