Jaccard Similarity F# http://en.wikipedia.org/wiki/Jaccard_index Good for fuzzy searching

jaccard.fs

let jaccard (a:string) (b:string) = 
	let set1 = Set.ofSeq a
	let set2 = Set.ofSeq b
	if Set.isEmpty set1 && Set.isEmpty set2
	then
		1.0
	else
		let i = Set.intersect set1 set2
		let u = set1 + set2		
		(float)(Set.count i) / (float)(Set.count u)

jaccard "hello world" "helo wrd"
|> printfn "%A"