兩個(gè)列表中的公共元素我有兩個(gè)ArrayList對(duì)象，每個(gè)對(duì)象具有三個(gè)整數(shù)。我想找到一種方法來返回這兩個(gè)列表的共同元素。有誰知道我怎么做到的嗎？
3 回答
慕村9548890
TA貢獻(xiàn)1884條經(jīng)驗(yàn) 獲得超4個(gè)贊
Stream.filter()List.contains():
import static java.util.Arrays.asList;
import static java.util.stream.Collectors.toList;
/* ... */
List<Integer> list1 = asList(1, 2, 3, 4, 5);
List<Integer> list2 = asList(1, 3, 5, 7, 9);
List<Integer> common = list1.stream().filter(list2::contains).collect(toList());
胡子哥哥
TA貢獻(xiàn)1825條經(jīng)驗(yàn) 獲得超6個(gè)贊
listA.retainAll(listB);// listA now contains only the elements which are also contained in listB.
listA
List<Integer> common = new ArrayList<Integer>(listA);common.retainAll(listB); // common now contains only the elements which are contained in listA and listB.
Qyouu
TA貢獻(xiàn)1786條經(jīng)驗(yàn) 獲得超11個(gè)贊
您可以在您的ArrayList物品。
就像這樣：
List<Integer> l1 = new ArrayList<Integer>();
l1.add(1);
l1.add(2);
l1.add(3);
List<Integer> l2= new ArrayList<Integer>();
l2.add(4);
l2.add(2);
l2.add(3);
System.out.println("l1 == "+l1);
System.out.println("l2 == "+l2);
List<Integer> l3 = new ArrayList<Integer>(l2);
l3.retainAll(l1);
System.out.println("l3 == "+l3);
System.out.println("l2 == "+l2);
現(xiàn)在,l3之間應(yīng)該只有共同的元素l1和l2.
CONSOLE OUTPUT
l1 == [1, 2, 3]
l2 == [4, 2, 3]
l3 == [2, 3]
l2 == [4, 2, 3]
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