I use the following function to calculate the maximum nesting deep of a list:
(cond ((null? lst) 0)
((atom? lst) 0)
(true (max (+ 1 (nesting (first lst)))
(nesting (rest lst))))
)
)
(nesting '(a (((b c (d)))) (e) ((f)) g))
;-> 5
Is there a better/faster way to do this?
Thanks.
Here's another way to do it.
(if (null? lst) 0
(atom? lst) 0
(+ 1 (apply max (map nesting lst)))))
You be the judge if it's "better". Beware though that, although the code length is shorter, timing tests show that it is slightly *slower* than the original.
The magic of "map" :-)
Not very elegant but maybe faster (for short lists I presume)
(define (nesting lst prev (t 0))
(if (= lst prev)
t
(nesting (flat lst 1) lst (inc t))))
> (nesting '(a (((b c (d)))) (e) ((f)) g))
5
Excellent, fdb! Faster than mine by about a factor of 3 (on the sample input)! 2.5 times faster than the original.
Wow!!!
Thanks fdb