Functions introduction

Set functions are used to inspect and manipulate sets of domains.

Some functions return new sets, others return Boolean values. For example, the CLONE function returns a new set that is an exact copy of an existing set:

var copyOfAll;

copyOfAll = CLONE(ALL);

Meanwhile, the EMPTY function checks if a set is empty, returning a Boolean value.

var copyOfAll;

copyOfAll = CLONE(ALL);

if (EMPTY(copyOfAll)) {
    ...
}

Set functions can be used:

• To give a value to set variables.
• As arguments of other functions.
• In complex expressions.

The available functions are listed in the following table and are described in the next pages of this section.

Function	Use
CLAN	Get domains from the project's taxonomy
CLEAN	Filter domains based on their score
CLONE	Copy a set
DIFFERENCE	Subtract a set from another
DIMENSIONS	Check the size of a set
EMPTY	Check if a set is empty
EXIST	Check if a set contains a domain
EXTRACT	Check if a set contains domains in a list
EXTRACT2	Get a portion of a set based on position
FAMILY	Get a portion of a set based on project's taxonomy
FILTER	Get a portion of a set based on relative ranking
FIRST	Get the top ranking domain
INSERT	Add domains to a set
INTERSECTION	Get the domains that two sets have in common
MULTIPLY	Change the score of domains
RATIO	Compare the score of two domains or two sets
RATIO2	Compare the score of a domain or set with a fraction of the score of another domain/set
REMOVE	Remove a domain from a set
SCORED	Get a domain based on its ranking
SECOND	Return the domain with the second highest score
SET	Create a new set from scratch
THRESHOLD	Filter set domains based on a comparison with the score of a given domain
THRESHOLD2	Filter set domains based on a comparison with a fraction of the score of a given domain
TRANSFORM	Transfer scores and rule information among domains
UNION	Add a set to another