Description
Removes all elements satisfying Predicate using RemoveAtSwap internally, which replaces each removed element with the last element rather than shifting. This is faster than RemoveAll when element order is not important.
Caveats & Gotchas
- • Element order is NOT preserved — removed positions are filled by swapping in the last element. Never use this when the array's iteration order has semantic meaning (e.g. a priority queue or an ordered list rendered to UI).
- • The predicate is called once per element in a simple forward pass with no run-length optimisation. RemoveAll (order-preserving) uses a more cache-friendly run-length pass and may be faster on arrays where most elements are removed.
Signature
template <class PREDICATE_CLASS>
SizeType RemoveAllSwap(const PREDICATE_CLASS& Predicate, EAllowShrinking AllowShrinking = UE::Core::Private::AllowShrinkingByDefault<AllocatorType>())Parameters
| Name | Type | Description | Default |
|---|---|---|---|
| Predicate | const PREDICATE_CLASS& | A callable that returns true for elements to remove. | — |
| AllowShrinking | EAllowShrinking | Whether to allow the allocator to shrink after removal. | UE::Core::Private::AllowShrinkingByDefault<AllocatorType>() |
Return Type
SizeType Example
Remove all dead actors from a spawn list C++
TArray<AActor*> SpawnedActors;
SpawnedActors.RemoveAllSwap([](AActor* A)
{
return !IsValid(A);
});Tags
Version History
Introduced in: 4.0
| Version | Status | Notes |
|---|---|---|
| 5.6 | stable | — |
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