数组重复值和数组去重

判断数组中是否有重复的值

Integer[] ia = new Integer[] { 1, 2, 3, 1 };
        Set<Integer> set = new HashSet<Integer>();
        for (Integer i : ia) {
            if (!set.add(i)) {
                System.out.println(i + "重复");
                break;
            }
        }

 

数组中的值去重复

Integer[] ia = new Integer[] { 1, 2, 3, 1 };
        Set<Integer> set = new LinkedHashSet<Integer>();
        for (Integer i : ia) {
            set.add(i);
        }
        System.out.println(set);
        ia = set.toArray(new Integer[0]);
    }

 

集合包含

        Set<Integer> set = new HashSet<Integer>();
        set.add(1);
        set.add(2);
        
        Set<Integer> otherSet = new HashSet<Integer>();
        otherSet.add(2);
        otherSet.add(1);
        
        System.out.println(set.containsAll(otherSet)); //true
        
        otherSet.add(3);
        System.out.println(set.containsAll(otherSet)); //false

A = {1,2}
B = {1,2,3}
A ⊆ B
A < B

Set

java.util.Set
A collection that contains no duplicate elements.