The Help file topic "How to reference parts of aggregate properties" should provide you with the details to get this accomplished.

From the Help file:

<LAST> index

To set or retrieve an element value from the end (highest index value) of a Value List or Page List property, use the <LAST> index keyword.

For example, this sets the value of the highest numbered element in the Month Value List property:

Lu

Leo, i have already gone through the help. My requirement is not to  "To set or retrieve an element value from the end (highest index value) of a Value List " but from the middle, as in - the valuelist  size is say 20, i might be iterating on loop 12 - i need the index for this loop as well as the index of loop 11. 

Getting any one index will resolve the problem, coz if i get the value of the current index, i will set the value to a local variable and will be able to get the index of the previous iteration.

If you already in loop, then try using pyForEachCount parameter to get the current loop index

Hi,

You can use Param.pyForEachCount parameter for current loop index, to get the value of the last iterated valuelist you can use Param.pyForEachCount -1 and get the value for that last iterated value from valuelist.