Question

I want to increment an index on a particular value, for example 2:

for (int i = 0; i < 10; i+=2)
{
    Console.WriteLine(i);
}

How do I do the same using the Parallel class, like:

Parallel.For(0, 10, i =>
{
    Console.WriteLine(i);
    i += 2; //this a naïve assumption, it's not working
});

Edit

I would like the Parallel loop to run only 5 operations (as the sequential for) and order doesn’t matter for me.

Answer 1

The implicit assumption in the first loop is that j is incremented sequentially.
In the second example the value of j can be any of 0 -> 9 in any of the loops.

You can achieve the same behaviour by the following:

Parallel.ForEach(Enumerable.Range(0, 5).Select(i => i*2), i =>
{
  Console.WriteLine(i);
});