The act of a function calling itself, recursion is used to solve problems that contain smaller sub-problems. A recursive function can receive two inputs: a base case (ends recursion) or a recursive case (resumes recursion).
Examples
Recursive function calls itself until condition met
The following Python code defines a function that takes a number, prints it, and then calls itself again with the number's value -1. It keeps going until the number is equal to 0, in which case it stops.
def recurse(x):
if x > 0:
print(x)
recurse(x - 1)
recurse(10)
The output will look like this:
10
9
8
7
6
5
4
3
2
1
0