Moving value of decimal array to other decimal array or any variable

Hi,

    I am trying to move the value of decimal array to one variable like lv_amount := :amount[:lv_index]; it is giving error but when i move the data from variable to array then it is working fine.

declare result_rate decimal(11, 2) array;

declare source_rate decimal(11, 2) array;

i have values in result_rate array and i want to move the values from result_rate array to souce_rate array but it is not accepting when i move the values directly using below statements

Error statement

lv_rate := :result_rate[:lv_index];   OR

source_rate[lv_index] := :result_rate[:lv_index];

But i found the below statements are working fine.

Statements working fine are

result_rate[:lv_index] := :lv_rate;

result_rate[:lv_index] := 100.00;

Can anybody please help me if any other way to move the decimal values from array to array.

Thanks in advance,

Venkatesh