Description
Adds an element only if it is not already present in the array. Returns the index of the existing or newly added element.
Signature
UE_FORCEINLINE_HINT SizeType AddUnique(ElementType&& Item)Parameters
| Name | Type | Description | Default |
|---|---|---|---|
| Item | ElementType&& | The element to add if not already present. | — |
Return Type
int32 Caveats & Gotchas
- • Performs a linear scan (O(n)) to check for duplicates — do not use in hot paths on large arrays. Consider TSet for O(1) uniqueness guarantees.
- • Uses operator== for comparison, so the element type must implement equality. For pointer arrays, this compares pointer values (addresses), not pointed-to objects.
- • Returns the index of the existing element if a duplicate is found, not -1 or an error. Check the array size before and after to determine whether insertion occurred.
Example
Maintain a unique list of interacting actors C++
TArray<AActor*> UniqueOverlaps;
void AMyActor::OnOverlapBegin(AActor* OtherActor)
{
UniqueOverlaps.AddUnique(OtherActor);
}
void AMyActor::OnOverlapEnd(AActor* OtherActor)
{
UniqueOverlaps.Remove(OtherActor);
}See Also
Tags
Version History
Introduced in: unknown
| Version | Status | Notes |
|---|---|---|
| 5.6 | stable | — |
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