Getting error while select 20 record for first time in FOR loop and rest for anther time in oracle

In Oracle, total 36 record i am getting by using PL/SQL variable type v_arr is varray(25) of varchar2(20). Inside the PL/SQL block i am using 2 different FOR loop for 2 different operation. in the 1st time i am using

For i in 1 .. v_arr.count(20) loop

and for the next time i used for i in v_arr.count(21) .. v_arr.count loop.

after compile i got error in both the condition. How to resolve this issue. Please help me.

Building on Barbaros' example, perhaps you wanted something like this:

declare
    type a_arr is table of varchar2(20);
    arr  a_arr := a_arr
         ( 'un1','un2','un3','un4','un5','un6','un7','un8','un9','un10'
         , 'un11','un12','un13','un14','un15','un16','un17','un18','un19','un20'
         , 'x1','x2','x3' );
begin  
    for i in 1..least(arr.count,20) loop
        dbms_output.put_line(arr(i));
    end loop;

    if arr.count > 20 then
        for i in 21..arr.count loop
            dbms_output.put_line(arr(i));
        end loop;
    end if;        
end;