From Python, to Java, Split ArrayList using Set()

Question

This is the code in Python I'm trying to convert to Java:

self.active = set(self.genes[-self.output_length:]):

Reading up on the sets in Python, I believe that this is splitting the ArrayList at the index of 'self.output_length'. Is this correct? A little background: the 'self.genes' contains genes which present both 'self.output_length' and 'self.nodes'.

Could I used this in Java:

List<float[]> temp = this.genes.subList(0,this.output_length);
this.active = Set(Collections.reverse(temp));

UPDATE: As per a previous answer, I've now done this:

List<float[]> temp = this.genes.subList(this.genes.size() - this.output_length, this.genes.size()); 
this.active = new ArrayList<float[]> (temp);

Thanks for your help.

Answer 1

If you want to use an ordered set in Java, use one of implementations of SortedSet. You need not to reverse the order of List before filling the Set, as it has no effect. To provide required ordering, pass a Comparator to the Set's implementation constructor.