FHIRPath Function: isDistinct

Returns true if all the items in the input collection are distinct. To determine whether two items are distinct, the equals (=) operator is used, as defined below.

Conceptually, this function is shorthand for a comparison of the count() of the input collection against the count() of the distinct() of the input collection:

X.count() = X.distinct().count()

This means that if the input collection is empty ({ }), the result is true.

Summary

• Category: Existence
• Section: 5.1.12
• Return Type: Boolean
• Empty Input Result: true
• Errors on Multiple Input: false

Description

Returns true if all the items in the input collection are distinct. To determine whether two items are distinct, the equals (=) operator is used.

Arguments

• none

Type Mapping

• Any-Boolean

Example

Patient.identifier.isDistinct() // returns true if all identifiers are unique