<status value="active"/><experimental value="false"/><date value="2021-01-05T10:01:24+11:00"/><publisher value="HL7 (FHIR Project)"/><contact><telecom><system value="url"/><value value="http://hl7.org/fhir"/></telecom><telecom><system value="email"/><value value="fhir@lists.hl7.org"/></telecom></contact><description value="The kind of operation to perform as a part of a property based filter."/><jurisdiction><coding><system value="http://unstats.un.org/unsd/methods/m49/m49.htm"/><code value="001"/><display value="World"/></coding></jurisdiction><caseSensitive value="true"/><valueSet value="http://hl7.org/fhir/ValueSet/filter-operator"/><content value="complete"/><concept><code value="="/><display value="Equals"/><definition value="The specified property of the code equals the provided value."/></concept><concept><code value="is-a"/><display value="Is A (by subsumption)"/><definition value="Includes all concept ids that have a transitive is-a relationship with the concept Id provided as the value, including the provided concept itself (include descendant codes and self)."/><property><code value="comments"/><valueString value="The definition of is-a is that all the properties of the value are true for the specified property of the code, which means that a code has an is-a relationship with itself. To exclude the root code, use descendent-of"/></property></concept><concept><code value="descendent-of"/><display value="Descendent Of (by subsumption)"/><definition value="Includes all concept ids that have a transitive is-a relationship with the concept Id provided as the value, excluding the provided concept itself (i.e. include descendant codes only)."/><property><code value="comments"/><valueString value="The definition of is-a is that all the properties of the value are true for the specified property of the code. Spelling note: "descendant" is a more correct spelling, but the spelling "descendent" is maintained in the code for backwards compatibility reasons"/></property></concept><concept><code value="is-not-a"/><display value="Not (Is A) (by subsumption)"/><definition value="The specified property of the code does not have an is-a relationship with the provided value."/></concept><concept><code value="regex"/><display value="Regular Expression"/><definition value="The specified property of the code matches the regex specified in the provided value."/></concept><concept><code value="in"/><display value="In Set"/><definition value="The specified property of the code is in the set of codes or concepts specified in the provided value (comma-separated list)."/></concept><concept><code value="not-in"/><display value="Not in Set"/><definition value="The specified property of the code is not in the set of codes or concepts specified in the provided value (comma-separated list)."/></concept><concept><code value="generalizes"/><display value="Generalizes (by Subsumption)"/><definition value="Includes all concept ids that have a transitive is-a relationship from the concept Id provided as the value, including the provided concept itself (i.e. include ancestor codes and self)."/><property><code value="comments"/><valueString value="The definition of is-a is that all the properties of the value are true for the specified property of the code, which means that a code has an is-a relationship with itself. To exclude the root code, add it explicitly to as an exclude"/></property></concept><concept><code value="child-of"/><display value="Child Of"/><definition value="Only concepts with a direct hierarchical relationship to the index code and no other concepts. This does not include the index code in the output."/></concept><concept><code value="descendent-leaf"/><display value="Descendent Leaf"/><definition value="Includes concept ids that have a transitive is-a relationship with the concept Id provided as the value, but which do not have any concept ids with transitive is-a relationships with themselves."/></concept><concept><code value="exists"/><display value="Exists"/><definition value="The specified property of the code has at least one value (if the specified value is true; if the specified value is false, then matches when the specified property of the code has no values)."/></concept></CodeSystem>

This code system http://hl7.org/fhir/filter-operator defines the following codes:

Code	Display	Definition	Comments
=	Equals	The specified property of the code equals the provided value.
is-a	Is A (by subsumption)	Includes all concept ids that have a transitive is-a relationship with the concept Id provided as the value, including the provided concept itself (include descendant codes and self).	The definition of is-a is that all the properties of the value are true for the specified property of the code, which means that a code has an is-a relationship with itself. To exclude the root code, use descendent-of
descendent-of	Descendent Of (by subsumption)	Includes all concept ids that have a transitive is-a relationship with the concept Id provided as the value, excluding the provided concept itself i.e. include descendant codes only).	The definition of is-a is that all the properties of the value are true for the specified property of the code. Spelling note: "descendant" is a more correct spelling, but the spelling "descendent" is maintained in the code for backwards compatibility reasons
is-not-a	Not (Is A) (by subsumption)	The specified property of the code does not have an is-a relationship with the provided value.
regex	Regular Expression	The specified property of the code matches the regex specified in the provided value.
in	In Set	The specified property of the code is in the set of codes or concepts specified in the provided value (comma-separated list).
not-in	Not in Set	The specified property of the code is not in the set of codes or concepts specified in the provided value (comma-separated list).
generalizes	Generalizes (by Subsumption)	Includes all concept ids that have a transitive is-a relationship from the concept Id provided as the value, including the provided concept itself (i.e. include ancestor codes and self).	The definition of is-a is that all the properties of the value are true for the specified property of the code, which means that a code has an is-a relationship with itself. To exclude the root code, add it explicitly to as an exclude
exists	Exists	The specified property of the code has at least one value (if the specified value is true; if the specified value is false, then matches when the specified property of the code has no values).
child-of	Child Of	Only concepts with a direct hierarchical relationship to the index code and no other concepts. This does not include the index code in the output.
descendent-leaf	Descendent Leaf	Includes concept ids that have a transitive is-a relationship with the concept Id provided as the value, but which do not have any concept ids with transitive is-a relationships with themselves.