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如两个数组或两个集合
Integer[] arr1 = {1,2,3,5,6};
Integer[] arr2 = {2,4,5,7};
求两者之间的交集
List<Integer> list1 = Arrays.asList(arr1);
List<Integer> list2 = Arrays.asList(arr2);
// 创建集合 求交集
Collection<Integer> c1 = new ArrayList<Integer>(list1);
Collection<Integer> c2 = new ArrayList<Integer>(list2);
c1.retainAll(c2);
System.out.println("arr1与arr2交集结果:" + c1);
求两者之间的并集
Set result = new HashSet();
result.addAll(list1);
result.addAll(list2);
System.out.println("并集结果:" + result);
求arr1存在的元素,arr2不存在,同理也可获得arr2存在的元素,arr1不存在
List<Integer> l1 = new ArrayList<Integer>();
for(int i = 0; i < len1; i++) {
Integer num = list1.get(i);
if (!list2.contains(num)) {
l1.add(num);
}
}
System.out.println("arr1集合中存在的元素但是arr2中不存在 :" + l1);