Functions such as as groups from gather the attributes in a set together by their containing groups. If there is a single attribute from a group, then the group will be represented by that attribute name, but for more than one attribute, the group name is used. For example, for a case with
Dog (65.11), Birch (63.60), Cat (52.1) and Eucalypt (52.1)
the expression
{allergens} in range [50, 5000] as groups from {food, pollen, mite, mould, animal}
will evaluate to
animal and pollen
This default behaviour can be modified by the use of the clause with {GroupLength=n} where ‘n’ is the number of attributes to allow from a group before representing
that group by its name. For example, for the case above the expression
{allergens} in range [50, 5000] as groups from {food, pollen, mite, mould, animal} with {GroupLength=2}
will evaluate to
Dog, Birch, Cat and Eucalypt
whereas for the case
Tiger (192), Dog (65.11), Birch (63.60), Cat (52.1) and Eucalypt (52.1)
the exrpession will evaluate to
animal, Birch and Eucalypt
This GroupLength syntax can be applied to the functions not in, intersect, union, and as groups from.