Documentation:OCLOperators asSet

OCLOperators asSet

This page was created by Alexandra on 2017-08-13. Last edited by Wikiadmin on 2026-07-29.

You use asSet() in OCL expressions when you need a duplicate-free, unordered Set from a value or another collection.

Signature

asSet() : Set(T)

asSet() returns a Set containing the elements of self. A Set is an unordered collection: it contains each element at most once.

Use asSet() when an expression returns a collection that may contain repeated values and the next part of the expression requires unique elements.

For example, this Sequence contains 'EmailAddress' twice:

Sequence{'String', 'EmailAddress', 'EmailAddress'}->asSet()

Result:

Set{'String', 'EmailAddress'}

The duplicate 'EmailAddress' is removed. Do not rely on the displayed order of the result: a Set is unordered.

When self is one value, asSet() creates a Set with that value as its single element.

'EmailAddress'->asSet()

Result:

Set{'EmailAddress'}

This is useful when you must supply a Set to a later collection expression but currently have one value.

For example, convert repeated integers to a Set before applying collect:

Sequence{14, 22, 14}->asSet()->collect(i | DoSomthingWithAnInt(i))

DoSomthingWithAnInt(i) is evaluated once for 14 and once for 22, because the Set has no duplicates.

Situation	Use `asSet()`?	Reason
You need unique elements from an existing collection	Yes	It returns a Set and removes duplicates.
You have one value but need a Set	Yes	It wraps the value in a one-element Set.
You need to preserve collection order	No	A Set is unordered; use Sequence when order matters.
You are creating a fixed Set directly	Usually no	Create it with `Set{...}`; see Set.