[Tutor] recursion surprise

[Alan Gauld]

On 09/06/13 02:56, Jim Mooney wrote:

> Well, for simple stuff. I'm now trying more complicated stuff and
> getting "maximum recursion depth exceeded" but that will give me fun

One of the snags with recursion in Python (and several other
languages) is that there is an arbitrary limit on how often
you can recurse. This is one (of several) reasons why recursion
should be used in moderation in real-world problems.

The good news is that
1) recursion can  lead to simple and elegant solutions
2) recursion can always be unwrapped into traditional loops

This means you can use recursion to discover the pure solution
then unwrap the recursion to get an industrial strength
(but ugly) solution that works.

Finally note that some languages (notably Lisp dialects)
are designed to use recursion and have specific mechanisms
to get round the limitations found in Python etc.

-- 
Alan G
Author of the Learn to Program web site
http://www.alan-g.me.uk/