This code system http://hl7.org/fhir/filter-operator defines the following codes:
Code
|
Display
|
Definition
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Comments
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=
|
Equals |
The specified property of the code equals the provided value. |
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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. |
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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). |
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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). |
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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). |
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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. |
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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. |
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