java list 去除 重复值
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2022-03-21 19:23:02
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一:
Hastset根据hashcode判断是否重复,数据不会重复
Java代码
/** List order not maintained **/
public static void removeDuplicate(ArrayList arlList)
{
HashSet h = new HashSet(arlList);
arlList.clear();
arlList.addAll(h);
}
二:
通过Hashset的add方法判断是否已经添加过相同的数据,如果已存在相同的数据则不添加
Java代码
/** List order maintained **/ public static void removeDuplicateWithOrder(ArrayList arlList) { Set set = new HashSet(); List newList = new ArrayList(); for (Iterator iter = arlList.iterator(); iter.hasNext(); ) { Object element = iter.next(); if (set.add(element)) newList.add(element); } arlList.clear(); arlList.addAll(newList); }
以下来自网络:
方法一:循环元素删除
// 删除ArrayList中重复元素 public static void removeDuplicate(List list) { for ( int i = 0 ; i i; j -- ) { if (list.get(j).equals(list.get(i))) { list.remove(j); } } } System.out.println(list); }
方法二:通过HashSet剔除
// 删除ArrayList中重复元素 public static void removeDuplicate(List list) { HashSet h = new HashSet(list); list.clear(); list.addAll(h); System.out.println(list); }
方法三: 删除ArrayList中重复元素,保持顺序
// 删除ArrayList中重复元素,保持顺序 public static void removeDuplicateWithOrder(List list) { Set set = new HashSet(); List newList = new ArrayList(); for (Iterator iter = list.iterator(); iter.hasNext();) { Object element = iter.next(); if (set.add(element)) newList.add(element); } list.clear(); list.addAll(newList); System.out.println( " remove duplicate " + list); } 自己使用: 删除 “0.0”的值 List> list1 = (List
>) map.get("商品入库表"); //表1 入库详细表 //删除list中 数量为 0值 for (Iterator
> item = list1.iterator(); item.hasNext(); ) { List
it = item.next(); System.out.print(it); if (it.get(4).equals("0.0")) { item.remove(); } }
链接地址:http://iteye.blog.163.com/blog/static/186308096201302565345510/