What is recursion?

Recursion is the process of repeating items in a self-similar way. In programming languages, if a program allows you to call a function inside the same function, then it is called a recursive call of the function.

Python Recursive Function

In Python, we know that a function can call other functions. It is even possible for the function to call itself. These types of construct are termed as recursive functions.

Factorial of a number is the product of all the integers from 1 to that number. For example, the factorial of 3 (denoted as 3!) is 3*2*1. Quesition is that how to implement this function in python?

In the above example, factorial() is a recursive function as it calls itself. When we call this function with a positive integer, it will recursively call itself by decreasing the number. Each function multiplies the number with the factorial of the number below it until it is equal to one.

Our recursion ends when the number reduces to 1. This is called the base condition. Every recursive function must have a base condition that stops the recursion or else the function calls itself infinitely.