4 去重(distinct)

package com.gp6.list.distinct;

import java.util.ArrayList;
import java.util.List;
import java.util.stream.Collectors;

/**
 * 測試list去重
 *
 * @author gp6
 * @date 2019-07-23
 */
public class TestDistinct {
    public static void main(String[] args) {
        List<Integer> list = new ArrayList<Integer>() {{
            add(1);
            add(2);
            add(1);
            add(3);
        }};

        // 去重處理,distinct基於Object.equals(Object)實現
        List<Integer> distinctList = list.stream().distinct().collect(Collectors.toList());
        // [1,2,3]
        System.out.println(distinctList);

        long count = list.stream().distinct().count();
        // 3
        System.out.println(count);

    }
}