Hi Bruno, > I'm surprised that (pick '((A B) (and (= A Value) B)) ListA ListB) is > faster than (get ListB (index Value ListA)).
> It's true that get traverses ListB right after a traversal of ListA, but > pick seems to do the same traversal of > the same number of elements. The only difference is that pick traverses the > two lists at the same time, instead > of sequentially. Oops, you are right! I have not tested, but the 'pick' solution is probably *slower* than the get/index one, due to the function call overhead for each element. I think I never needed such a case. Usually I try do build 'assoc'iation list for such purposes. That is probably the fastest, and surely most lispy :) - Alex -- UNSUBSCRIBE: mailto:firstname.lastname@example.org?subject=Unsubscribe