set: set the value of the item $index (from 0 to n-1) with the value $value, or all values from a list {value_1 ... value_n}. To set some index the array space must be allocated previously with a size greater of the index.
objarray set <obj> {<value_1> ... <value_n>}|<index> <value>
e.g.
set obj [objarray new intarray 3 0]
-> 0 0 0
objarray set $obj {6 3 8}
-> 6 3 8