检查列表是否包含多个元素的便捷方法

Question

How can I check if a list of strings contains some specific strings at the same time, without having to do multiple contains.

For example something like this:

if (templist.contains("aaa") && templist.contains("bbb")) {

}

Answer 1

List.containsAll function can actually achieve your requirement. However, using containsAll with list type can degrade in performance as the order is O(NK) where N is the number of elements of the list and K is the number of target string. Try using a HashSet to improve the performance:

   HashSet<String>set = new HashSet<>(list);
   if(set.containsAll(Arrays.asList("asd", "efg")))
        // do my job; 

Because, HashSet<E> class offers constant time performance for the basic operations ( add, remove, contains and size ). As containsAll inherently uses the contains function to look up the element the order can be expected as O(N+K)

Answer 2

You can use containsAll

if (templist.containsAll(Arrays.asList("aaa", "bbb"))) {
    // do something
}