List集合去除重複資料 Java中List集合去除重複資料的方法
阿新 • • 發佈:2018-10-31
【轉自】Java中List集合去除重複資料的方法
1. 迴圈list中的所有元素然後刪除重複
public static List removeDuplicate(List list) { for ( int i = 0 ; i < list.size() - 1 ; i ++ ) { for ( int j = list.size() - 1 ; j > i; j -- ) { if (list.get(j).equals(list.get(i))) { list.remove(j); } } }return list; }
2. 通過HashSet踢除重複元素
public static List removeDuplicate(List list) { HashSet h = new HashSet(list); list.clear(); list.addAll(h); return list; }
3. 刪除ArrayList中重複元素,保持順序
// 刪除ArrayList中重複元素,保持順序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); }
4.把list裡的物件遍歷一遍,用list.contain(),如果不存在就放入到另外一個list集合中
public static List removeDuplicate(List list){ List listTemp = new ArrayList(); for(int i=0;i<list.size();i++){ if(!listTemp.contains(list.get(i))){ listTemp.add(list.get(i)); } } return listTemp; }
轉載:http://blog.csdn.net/u011728105/article/details/46594963
1. 迴圈list中的所有元素然後刪除重複
public static List removeDuplicate(List list) { for ( int i = 0 ; i < list.size() - 1 ; i ++ ) { for ( int j = list.size() - 1 ; j > i; j -- ) { if (list.get(j).equals(list.get(i))) { list.remove(j); } } } return list; }
2. 通過HashSet踢除重複元素
public static List removeDuplicate(List list) { HashSet h = new HashSet(list); list.clear(); list.addAll(h); return list; }
3. 刪除ArrayList中重複元素,保持順序
// 刪除ArrayList中重複元素,保持順序 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); }
4.把list裡的物件遍歷一遍,用list.contain(),如果不存在就放入到另外一個list集合中
public static List removeDuplicate(List list){ List listTemp = new ArrayList(); for(int i=0;i<list.size();i++){ if(!listTemp.contains(list.get(i))){ listTemp.add(list.get(i)); } } return listTemp; }
轉載:http://blog.csdn.net/u011728105/article/details/46594963