Question

我正在寻找一种从列表中删除重复项的好方法。

List<String[]> rowList = new ArrayList();
    rowList.add(new String[]{"1","a", "abc"});
    rowList.add(new String[]{"2","b", "def"});
    rowList.add(new String[]{"3","c", "ghi"});
    rowList.add(new String[]{"4","a", "jkl"});
    rowList.add(new String[]{"5","d", "mno"});
    rowList.add(new String[]{"6","e", "pqr"});
    rowList.add(new String[]{"7","b", "stu"});

从这个rwoList，我只想要条目：1,2,3,5和6.这意味着我只有一列intrest，在这种情况下第2列（a，b，c，..）这只是一个简单的例子，我必须处理有300列和最少300000行的数量表。另一个重点是，我不会放弃列表中的方向。

注意：我从csv文件接收数据。

Answer 1

  List<String[]> rowList = new ArrayList<String[]>();
  rowList.add(new String[]{"1","a", "abc"});
  rowList.add(new String[]{"2","b", "def"});
  rowList.add(new String[]{"3","c", "ghi"});
  rowList.add(new String[]{"4","a", "jkl"});
  rowList.add(new String[]{"5","d", "mno"});
  rowList.add(new String[]{"6","e", "pqr"});
  rowList.add(new String[]{"7","b", "stu"});

  Set<String[]> s = new TreeSet<String[]>(new Comparator<String[]>() {
         @Override
         public int compare(String[] o1, String[] o2) {
                return o1[1].compareTo(o2[1]);
        }
   });

通过添加设置"s"

来删除重复项

   s.addAll(rowList);
   List<Object> res = Arrays.asList(s.toArray());

打印结果

   for (Object object : res) {
         String[] array = (String[])object;
         System.out.println(array[0]+" "+ array[1] +", "+array[2]);
    }

<强>输出

1 a, abc
2 b, def
3 c, ghi
5 d, mno
6 e, pqr

Answer 2

制作自定义方法isContain(List<String[]> rowList, String string)

private static boolean isContain(List<String[]> rowList, String secStr) {
    for (String[] strings : rowList) {
       if(strings[1].equals(secStr)){
           return true;
       }   
    }
    return false;
}

在将项目添加到List之前检查此方法以删除重复项目，例如：

 List<String[]> rowList = new ArrayList();
    String[] sts= new String[]{"1", "a", "abc"};
    boolean contain= isContain(rowList,sts[1]);
    if(!contain){
        rowList.add(sts);
    }

从List <string []> </string []>中删除重复项

2 个答案: