Adding an object into a list, creating a list of unique objects

When I add the same specific object to a list, do I create a list with the same object appearing in it multiple times or does this list always contains a set of unique objects?
1 answers

When you add the same object to a list, the object will appear in the list twice. For aggregate functions like sum, this means the same object will be counted twice. However, for list operations (like union, intersect) the lists are converted to a set which cannot contain duplicates.

So short answer: yes you can have a list with the same objects.