TArray::HeapPopDiscard

function Core Since 4.0

#include "Containers/Array.h"

Access: public

Description

Removes the top element from the heap without returning it, then re-heapifies. Use this instead of HeapPop when you need to discard the maximum element and don't need its value, avoiding a copy/move into a local.

Caveats & Gotchas

• Like HeapPop, calling this on an empty array is undefined and will trigger a bounds check. Guard with Num() > 0.
• The bool bAllowShrinking overload is deprecated in UE 5.x — use EAllowShrinking::Yes/No.
• Prefer HeapPopDiscard over HeapPop in tight loops where the top value is not needed, since it skips moving the element into an output variable.

Signature

void HeapPopDiscard(EAllowShrinking AllowShrinking = UE::Core::Private::AllowShrinkingByDefault<AllocatorType>())

Parameters

Name	Type	Description	Default
AllowShrinking	EAllowShrinking	Controls whether the array's allocation can shrink after removal.	UE::Core::Private::AllowShrinkingByDefault<AllocatorType>()

Return Type

void

Example

Trimming a heap to a maximum size C++

// Keep only the 5 smallest scores in a min-heap (using TGreater)
TArray<int32> MinHeap;
MinHeap.Heapify(TGreater<int32>());
for (int32 Score : IncomingScores)
{
    MinHeap.HeapPush(Score, TGreater<int32>());
    if (MinHeap.Num() > 5)
    {
        MinHeap.HeapPopDiscard(TGreater<int32>(), EAllowShrinking::No);
    }
}

Version History

Introduced in: 4.0

Version	Status	Notes
5.6	stable	—

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