如何在HashSet <arraylist <integer>＆gt;中打印出ArrayList <integer>？</arraylist <integer> </integer>

Question

如何打印出HashSet类型的索引＆gt;？

以下是代码：

HashSet<ArrayList<Integer>> possibleRoutes;

我试过

int indexOfMinDistance = routesDistances.indexOf(Collections.min(routesDistances));
System.out.println(possibleRoutes.indexOf(indexOfMinDistance));

该程序建议将possibleRoutes转换为List，因为它们的类型不同，会产生更多错误。那么如何打印索引，例如。 ArrayList<Integer>, of a HashSet<ArrayList<Integer>>?

Answer 1

如果您正在研究如何迭代哈希集，这可能会对您有所帮助..

  HashSet<ArrayList<Integer>> possibleRoutes = new HashSet<ArrayList<Integer>>();

  Iterator<ArrayList<Integer>> possList  =possibleRoutes.iterator();

  /* here u can't take out by index, hasset 
    makes no guarantees as to the iteration order of the set*/

  ArrayList<Integer>main = possList.next();  //but can loop through it by next which gives ArrayList<integer>
  for(Integer m : main)
 { System.out.println(m); }