Assume you having 20 target MovieClips(target1, target2 ,...,target20) and you have to set position of all in a fetch. Using the "this" operator you can do this

for(var i=0;i<=20;i++){
this['target'+i].y=i*20;
}

as well as you can set the variable like the same

for(var i=0;i<=20;i++){
this['variable'+i] = 20;
}