python recursive function that prints from 0 to n?

Question

I am trying to write a recursive function that prints from 0 to n, but I have no idea how to do it. I accidentally made one that prints from

Answer 1

You can replace the 0 and the n, and the + with a - to make your recursive countdown function to a recursive countup:

def countup(N, n=0):
    print(n)
    if n == N:
        return
    return countup(N, n + 1)

And call it as follows:

countup(3)

@JFSebastian points out this algorithm has the benefit of being O(1) rather than O(n), as discussed in this excellent article about the difference between a linear and iterative recursion, if used with the @tail_call_optimized decorator.