List去重有几种方式

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1、for循环添加去重

2、for 双循环去重

3、for 双循环重复坐标去重

4、Set去重

5、stream流去重

1、for循环添加去重

    List oldList = new ArrayList();        oldList.add("张三");        oldList.add("张三");        oldList.add("李四");        oldList.add("王五");        oldList.add("赵六");        List newList = Lists.newArrayList();        for (String name : oldList) {            if (!newList.contains(name)){                newList.add(name);            }        }        System.out.println("原本的集合原素"+oldList);        System.out.println("去重后的集合"+newList);        // An highlighted blockvar foo = 'bar';

打印结果如下：

2、for 双循环去重

   @Test    public void test77() {        List oldList = new ArrayList();        oldList.add("张三");        oldList.add("张三");        oldList.add("李四");        oldList.add("王五");        oldList.add("赵六");         for (int i = 0; i  i; j--) {                if (oldList.get(j).equals(oldList.get(i))) {                    oldList.remove(j);                }            }        }         System.out.println("原本的集合元素：" + oldList);    } }

打印结果如下：

3、for 双循环重复坐标去重

   @Test    void contextLoads4() {        List oldList = new ArrayList();        oldList.add("张三");        oldList.add("张三");        oldList.add("李四");        oldList.add("王五");        oldList.add("赵六");        List newList = Lists.newArrayList();        newList.addAll(oldList);        for (String name : newList) {            if (oldList.indexOf(name) != oldList.lastIndexOf(name)) {                oldList.remove(oldList.lastIndexOf(name));            }        }        System.out.println("原本的集合原素"+oldList);    }    // An highlighted blockvar foo = 'bar';

打印结果如下：

4、Set去重

    @Test    void contextLoads5() {        List oldList = new ArrayList();        oldList.add("张三");        oldList.add("张三");        oldList.add("李四");        oldList.add("王五");        oldList.add("赵六");        List newList = Lists.newArrayList(new HashSet(oldList));        System.out.println("原本的集合原素"+newList);    }    // An highlighted blockvar foo = 'bar';

打印结果如下：

5、stream流去重

    @Test    void contextLoads5() {        List oldList = new ArrayList();        oldList.add("张三");        oldList.add("张三");        oldList.add("李四");        oldList.add("王五");        oldList.add("赵六");        List collect = oldList.stream().distinct().collect(Collectors.toList());        System.out.println("原本的集合原素"+collect);    }    // An highlighted blockvar foo = 'bar';

打印结果如下：