Re: Best way to check if all elements in a List are unique

laredotornado wrote:


That depends largely on what you mean by "best", and somewhat on what you mean
by "check".

If the List contains exactly one element, then you already know that it's
unique, so the real problem doesn't come about until it has at least two elements.

One way is to dump the List into a Set as you iterate through the List, and
for each element see if it's already in the Set. (This is indicated by the
Set#add() returning false.)

If all you need to do is ensure that each element is unique, you can dump the
contents into a Set and use the Set. (The Set implementations with which I'm
familiar have constructors that take a Collection as the argument.)

If you have a choice about whether to use a List in the first place, just
don't, and use a Set instead.

Whether any of these constitute "best" I cannot tell from your question.

--
Lew