Difference operation support

[sunny-repo88]

Hi,

Thanks for this cool idea project with bit manipulation and great performance. Do u plan to support difference operation. This is the solution i can think of without bit manipulation. This might be the slowest.
Any solution can be faster than this?

setA := nset.NewNSet[uint32]()

setA.Add(0)
setA.Add(300)
setA.Add(256)
setA.Add(4)

setB := nset.NewNSet[uint32]()
setB.Add(0)
setB.Add(4)

setA = setA.Difference(setB)
fmt.Println(setA.GetAllElements()) //[256 300]

Possible solution

func (n *NSet[T]) Difference(otherSet *NSet[T]) *NSet[T] {
	outSet := n
	filter := otherSet.GetAllElements()
	for _, x := range filter {
		if outSet.Contains(x) {
			outSet.Remove(x)
		}
	}
	return outSet
}

[bloeys]

Hey,

Glad you liked the project.

So I think by difference you kind of mean set1.NotIn(set2), basically saying: 'create a set containing elements in set1 but not in set2`.

Did I get that right?
This seems like a nice thing to have and definitely should be able to speed this by playing with bits and such.

I am busy this week but perhaps I'll have time in ~10 days or so.

Thanks

[sunny-repo88]

Hi @bloeys , yes you are right.

[bloeys]

Hey @sunny-repo88

The function GetDifference has been added in this release https://github.com/bloeys/nset/releases/tag/v1.3.0 (Edit: Use v1.3.1 as v1.3.0 has a small bug)

Please check it out, and if all is good close the issue.

Hope nset proves useful :)

[sunny-repo88]

@bloeys , this looks good. thanks for the effort