Random element from AIAbstractList

[Bilbo]

Is there any effective way to "get random town" (or generally "pick random object from some AIAbstractList")?
I have tried with code:

Code: Select all

  local list=AITownList();
  local count=list.Count();
  local N=RandRange(count);

But ... you can get N-th value with list.Begin() and then list.Next(), but that is very ineffective, especially with lots of towns (you have to get through entire part of list to get to Nth element)

You can also valuate with RandItem and then pick first, but that is also ineffective.

Is there some better way for random access to list elements (aside from copying the entire list to some array, which may work, but may not be always appropriate, especially if you won't need the list after that) that won't require going over entire (or significant portion of) list?

Hmm .. maybe it would be nice idea to extend AIAbstractList with some GetRandomItem() function :)

[Zutty]

You can also valuate with RandItem and then pick first, but that is also ineffective.

Thats what I do. Its not slow if thats what you're worried about. Choosing 50 random numbers (average no towns for a 256 map) isn't a big deal compared to something like pathfinding.

[Bilbo]

Choosing 50 random numbers (average no towns for a 256 map) isn't a big deal compared to something like pathfinding.

Well, it is 50 times slower than picking just one random number. And if you do it multiple times, it will make a big difference....

Especially for large lists.