你可以使用集合.创建时会自动删除重复项.

You could use sets. Duplicates will be removed automatically upon creation.

NSArray *cleanedArray = [[NSSet setWithArray:dates] allObjects];

请记住，集合是无序的.

Bear in mind that a set is unordered.

根据 Brent 的评论，该问题的最新解决方案将允许您保持元素有序.

As per Brent's comment, a more recent solution to the problem that will allow you to keep the elements in order.

[[NSOrderedSet orderedSetWithArray:dates] array]