A different kind of "expressiveness."

    NB. naive k-nearest neighbors in J

    dist =: [:%:[:|[:+/(*:@:-)    NB. dyad takes two vectors, returns euclidean distance

    data =: 1 2 3,2 2 3,2 3 3,1 2 3,:2 3 4
    query =: 1 2 3
    k =: 3

    k {."1 /:"1 query&dist"1 data