Hi,
Even if the elements are not comparable, you could rely on the fact that
Collection(s) usually create iterators with stable iteration order, so
you could do the following:
Set<Integer> set = Set.of(1, 2, 3, 4);
Iterator<Integer> it1 = set.iterator();
for (int n1 = 0; it1.hasNext(); n1++) {
Integer e1 = it1.next();
Iterator<Integer> it2 = set.iterator();
for (int n2 = 0; n2 < n1; n2++) {
Integer e2 = it2.next();
System.out.println(e1 + " <-> " + e2);
}
}
Regards, Peter
On 09/11/2016 02:02 PM, Tagir F. Valeev wrote:
Hello!
As your keys are comparable, you can create normal iterators and
filter the results like this:
for(String v1 : s) {
for(String v2 : s) {
if(v1.compareTo(v2) < 0) {
System.out.println(v1 + " <-->" + v2);
}
}
}
Or using Stream API:
s.stream().flatMap(v1 -> s.stream()
.filter(v2 -> v1.compareTo(v2) < 0).map(v2 -> v1 + " <-->" + v2))
.forEach(System.out::println);
With best regards,
Tagir Valeev.
DB> It would be nice to be able to associate each element in a collection
DB> with another element in the collection, which is something very easily
DB> done with index based collections, but with sets, etc this isn't so
DB> easy... unless i'm having a brainfart.
DB> So i'd like to do this, but Iterator doesn't implement Cloneable... Any
DB> reason not to? or is there another way that's missing me?
DB> public class ItClone {
DB> public static void main(String[] args) {
DB> Set<String> s = Collections.newSetFromMap(new
DB> ConcurrentHashMap<String, Boolean>());
DB> s.add("Fee");
DB> s.add("Fi");
DB> s.add("Fo");
DB> s.add("Fum");
DB> Iterator<String> it1 = s.iterator();
DB> while (it1.hasNext()) {
DB> String v1 = it1.next();
DB> Iterator<String> it2 = (Iterator<String>) it1.*clone*();
DB> while (it2.hasNext()) {
DB> String v2 = it2.next();
DB> System.out.println(v1 + " <-->" + v2);
DB> }
DB> }
DB> }
DB> }
