An operation that applies to two sets. The simplest syntax is:
X intersect Y
where X and Y are sub-expressions giving sets.
If the sets are group attributes, it creates a set which contains only those attributes which appear in both sets (i.e. set intersection). The sets can be expressed in terms of either attribute or group names.
If the sets are attribute values, it creates a set which contains only those values which appear in both sets.
The simplest syntax is:
{ names_1 } intersect { names_2 }
or
{ values_1 } intersect { values_2 }
where:
names_1 and names_2 are comma separated lists of attribute or group attribute names
or
values_1 and values_2 are comma separated lists of attribute values
For example, suppose we have the calculated value attribute VeryHighAllergens defined as any allergen with value in the range [50, 100):
{pollen, food, mould, mite} in range [50, 100)
Then we could define the calculated value attribute VeryHighFoodAllergens simply as
VeryHighAllergens intersect {food}
As an example, consider the following case. Birch and timothy are in the pollen group. Milk, peanut, cod, soya, and wheat are in the food group. Birch, peanut and soya are very high allergens, but only two of these (peanut and soya) are in the food group.
age 1 sex F milk 16.0 peanut 73.5 cod 12.1 soya 64.6 wheat 25.3 birch 85.3 timothy 17.6 VeryHighAllergens birch (85.3), peanut (73.5) and soya (64.6) VeryHighFoodAllergens peanut (73.5) and soya (64.6)
See also: