Divide a set into smaller sets - Java

Question

I have a set, which I would like to divide into smaller sets of size x. Guava has something similar for lists - Lists.partition. But I couldn't find anything related to Sets. Are there any libraries which can help me in doing this? If not, what's the best way to break a set into smaller sets?

Edit: Currently, I'm doing it as follows:

int x = 10;
Set<String> stringSet = createHashSet();
for (List<String> partition : Iterables.partition(stringSet, x) {
    doSomething(new HashSet<>(partition));
}

I'm using this Iterables.partition. There should be better ways to do it, which doesn't involve converting set to a list, and then back to a set.

`Set` is by definition unordered so the partitioning logic which exists in Guava for `List` will not apply. You need to create something yourself for this, depending on the `Set` implementation class (`hash`, `tree`, etc..) — Kon, Sep 25 '15 at 22:26
Java 8? http://stackoverflow.com/questions/29095967/splitting-list-into-sublists-along-elements — Sully, Sep 25 '15 at 22:27
@SotiriosDelimanolis - I don't need any special partitioning logic. — Gengis Khan, Sep 25 '15 at 22:37
@Kon - I have a HashSet. I just want to break it into smaller sets and process those in batches. — Gengis Khan, Sep 25 '15 at 22:37
What are those smaller sets made of? What do they contain? Why? — Sotirios Delimanolis, Sep 25 '15 at 22:45

score 1 · Answer 1 · answered Sep 25 '15 at 22:31

Set<Integer> input = /*defined elsewhere*/;
int x = 10;

List<Set<Integer>> output = new ArrayList<>();
Set<Integer> currSet = null;
for (Integer value : input) {
    if (currSet == null || currSet.size() == x)
        output.add(currSet = new HashSet<>());
    currSet.add(value);
}

Result is, for all intends and purposes, random. It is undefined which elements of the input set going into which set of the output, and within an output set, the values will be in arbitrary order.

Divide a set into smaller sets - Java

1 Answers1