如何获取 List 或 Set 的第一个元素?
我想知道是否可以获取列表或集合的第一个元素.使用哪种方法?
I'd like to know if I can get the first element of a list or set. Which method to use?
推荐答案
Collection c;
Iterator iter = c.iterator();
Object first = iter.next();
(这是您最接近拥有 Set 的第一个"元素的方式.您应该意识到它对于大多数 Set. 这可能对 LinkedHashSet 和 TreeSet 有意义，但对 HashSet 没有意义.)
(This is the closest you'll get to having the "first" element of a Set. You should realize that it has absolutely no meaning for most implementations of Set. This may have meaning for LinkedHashSet and TreeSet, but not for HashSet.)
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