Description
Constructs a new element in-place at the given index, shifting all subsequent elements right by one. Avoids a temporary copy compared to Insert.
Caveats & Gotchas
- • Inserting at any position other than the end (Index == Num()) requires shifting all following elements, which is O(N). For order-insensitive use cases, prefer EmplaceAt with the last index or just Emplace to avoid the shift cost.
- • Index must be in the range [0, Num()] — inserting past the end asserts. Use Emplace (no index) to append.
Signature
template <typename... ArgsType>
UE_FORCEINLINE_HINT void EmplaceAt(SizeType Index, ArgsType&&... Args)Parameters
| Name | Type | Description | Default |
|---|---|---|---|
| Index | SizeType | The index at which to insert the new element. Existing elements at and after this index are shifted right. | — |
| Args | ArgsType&&... | Arguments forwarded directly to the element's constructor. | — |
Return Type
void Example
Insert a constructed element at the front C++
TArray<FHitResult> Hits;
// ... populate Hits ...
Hits.EmplaceAt(0); // default-constructs an FHitResult at index 0, shifting all othersSee Also
Tags
Version History
Introduced in: 4.14
| Version | Status | Notes |
|---|---|---|
| 5.6 | stable | — |
Feedback
Was this helpful?