How to work with a string named object?

…so, I have the following code
for (i=1; i<=n; i++) {
duplicateMovieClip(_root.object, “object”+i, i);
//how can I choose the position of the new MovieClip?
//“object”+i_x = random(100) - this should work if I had a different name of variable, but in this case it doesn’t.
//set(“object”+i_x, random(300)); - this doesn’t work neither