erlang jaccard 'bit' index
===

I am new to Erlang, so please forgive my naïvety. 

I am trying to re-write functions that I have written in other languages. One of them is the jaccard bit index.

in python haskell and clojure it would work as follows:

    xs = [1,1,0,0,1,1,0,0,1,1,0,0]
    ys = [1,0,1,0,1,0,1,0,1,0,1,0]
    
    # python 3.X
    def jaccard_bit_index(A,B):
        i = sum(map(operator.mul ,A,B)) 
        return  i / (sum(A) + sum(B) - i)
      
    -- haskell
    jaccrd_bit_index a b =
        count / ((sum a) + (sum b) - count)
        where
          count = sum $ zipWith (*) a b
    
    %% clojure
    (defn jaccard-bit-index [a b]
      (let [binarycount (apply + (map * a b))]
        (/ binarycount
           (- (+ (apply + a) (apply + b))
              binarycount))))


I think my problem is that I only know of Erlang's 

`map(Fun, List1) -> List2` 

and every time I have done it before I have used somethig similar to:

`map(Fun, List1, List2) -> List3`