I am knowingly going to take a bit of a heterodox view here, but in my opinion, this is actually the most functional of the solutions proposed: def factori

I am knowingly going to take a bit of a heterodox view here, but in my opinion, this is actually the most functional of the solutions proposed: def factorial(n): return prod(range(1, n + 1)) I think the essence of modern functional programming is not recursion per se, but the factoring out (no pun intended in this context) of recursion schemes and making them first-class citizens. Granted, to understand what is going on you need to understand the basics of recursion, so I'm not saying to skip that per se, but I don't think recursion should any longer be taught as the "distinctive characteristic" of this sort of modern functional programming. What's interesting is the factoring out of recursion schemes, the composition of recursion schemes with other recursion schemes (i.e., putting a filter on a map, as the simplest case), and the composition of recursion schemes with other functional tools. In practice, when programming in Haskell, you recurse a lot less than non-Haskell programmers may have the impression that you do, because you more often use these defined recursion schemes. Recursion is still used, certainly, but even then it's often as some one-off scheme that may be extracted later, or simply as a somewhat hacky way of tricking the compiler to do certain optimizations with no reference to "good code" at all. You can get a long way in Haskell without writing explicit recursion yourself.