Generator functions equivalent in Java

Question

I would like to implement an Iterator in Java that behaves somewhat like the following generator function in Python:

def iterator(array):
   for         


        

Answer 1

Indeed Java has no yield, but you can now use Java 8 streams. IMO it's really a complicated iterator since it's backed by an array, not a function. Given it's a loop in a loop in a loop can be expressed as a Stream using filter (to skip the nulls) and flatMap to stream the inner collection. It's also about the size of the Python code. I've converted it to an iterator to use at your leisure and printed to demonstrate, but if all you were doing was printing, you could end the stream sequence with forEach(System.out::println) instead of iterator().

public class ArrayIterate
{
    public static void main(String args[])
    {
        Integer[][][] a = new Integer[][][] { { { 1, 2, null, 3 },
                                                null,
                                                { 4 }
                                              },
                                              null,
                                              { { 5 } } };

        Iterator