Uint can't be null or NaN

i want my uint to be 0,1, or null.

it appears i cannot assign NaN to a uint, but i can with a number. why is that?


var num:Number;
trace (num) //NaN

var u:uint;
trace (u); //0

I want an undefined place holder for the uint. In my case i suppose I’ll use the number 2 and try to remember it means NaN to me.