Select random instance with instance variable=X

Hi!

I wonder if I can combine the "Pick random instance" with the "Compare instance variable". I'm making a Geography quiz using sprites as questions, and I would like to choose a random sprite from the un-answered ones.

In my test project I see that a mere combination of "Pick random instance" and "Compare instance variable" in same event does not work. Do you think putting one or the other as sub-event would work?

They do work in the same event but you need to change the order to

"compare instance variable" then "pick random instance".

I'm doing that and runs better in that order, but still repeating sometimes (i.e. picking instances without the right instance variable).

Is there a way to detect if there is no instance with the right variable at all? i.e., can I count the result of a "compare instance variable"?

If I can't, then I'll add a counter to detect if all instances have the variable already set.

Maybe your problem is about this issue: scirra.com/forum/r102-checking-the-instance-variable-is-passing_topic56623.html

When possible, it'll be repaired.

arcalaus

You could use the Sprite.PickedCount expression with the system compare condition to see how many are picked.

Those conditions work flawlessly for me. What other events are you using?