IN vs OR of Oracle, which faster?

Question

I\'m developing an application which processes many data in Oracle database.
In some case, I have to get many object based on a given list of conditions, and I use

Answer 1

If you create the table with a primary key:

CREATE TABLE my_test (id NUMBER,
CONSTRAINT PK PRIMARY KEY (id));

and go through the same SELECTs to run the query with the multiple IN values, followed by retrieving the execution plan via hash value, what you get is:

SELECT STATEMENT
INLIST ITERATOR
INDEX                  RANGE SCAN

This seems to imply that when you have an IN list and are using this with a PK column, Oracle keeps the list internally as an "INLIST" because it is more efficient to process this, rather than converting it to ORs as in the case of an un-indexed table.

I was using Oracle 10gR2 above.