Array Library

The Array Library is split into two classes. UNihiloArrayLibrary is a templated C++ library covering the full operation set. UNihiloArrayLibrary_BP exposes a typed Blueprint subset for common element types: Int32, Float, String, Vector, Object, and Actor.

info

All functions are stateless and return new arrays — none mutate the input. In C++, pass any element type via the templated versions. In Blueprint, use the typed suffix variants (e.g. Take_Int32).

Function	Description
Navigation
IncrementIndex	Advances CurrentIndex by 1. Behavior at the upper boundary is controlled by EArrayCycleMethod — Revolve wraps back to 0, Clamped stays at the last element. Outputs bPositionUpdated and BoundaryPosition.
DecrementIndex	Retreats CurrentIndex by 1 with the same boundary options as IncrementIndex.
IsValidArrayIndex	Returns true if Index is within [0, ArraySize).

Function	Description
Query (C++ only where noted)
TryGet	Returns the element at Index via OutResult and outputs true if the index is valid. Blueprint typed variants available.
GetOrDefault	Returns the element at Index, or DefaultValue if the index is out of bounds. Blueprint typed variants available.
FindFirst	Returns the first element matching a predicate via OutResult. C++ only.
FindLast	Returns the last element matching a predicate. C++ only.
FindAll	Returns all elements matching a predicate. C++ only.
FindIndex	Returns the index of the first matching element, or INDEX_NONE. C++ only.
FindIndices	Returns all indices of matching elements. C++ only.

Function	Description
Transformation
Filter	Returns a new array containing only elements that satisfy the predicate. C++ only.
Map	Projects each element to a new type via a transformer function, returning a TArray<U>. C++ only.
Flatten	Collapses a TArray<TArray<T>> into a single TArray<T>. C++ only.
Distinct	Removes duplicate elements, preserving first-occurrence order. Blueprint typed variants available.
DistinctBy	Removes duplicates using a key selector function rather than direct equality. C++ only.
Reverse	Returns a reversed copy of the array. Blueprint typed variants available.

Function	Description
Slicing
Take / TakeLast	Returns the first or last N elements. Clamped to array length. Blueprint typed variants available.
Skip / SkipLast	Returns all elements after skipping the first or last N. Blueprint typed variants available.
Slice	Returns a sub-array starting at StartIndex for up to Count elements. Blueprint typed variants available.
Chunk	Splits the array into a TArray<TArray<T>> of sub-arrays, each at most ChunkSize elements. C++ only.

Function	Description
Aggregate
CountWhere	Returns the number of elements matching a predicate. C++ only.
AnyMatch / AllMatch / NoneMatch	Predicate-based boolean checks against the array. C++ only.
Reduce	Left-folds the array into a single value using an accumulator and an initial seed. C++ only.
Sum / Average	Numeric aggregation. Average returns float; returns 0 on an empty array. Blueprint typed variants available for Int32 and Float.
Min / Max	Returns the smallest or largest element via an out parameter. Returns false on empty arrays. Blueprint typed variants available for Int32 and Float.

Function	Description
Set Operations
Union	Returns all unique elements from both arrays combined. Blueprint typed variants available.
Intersect	Returns elements present in both arrays. Blueprint typed variants available.
Difference	Returns elements in the first array that are absent from the second. Blueprint typed variants available.
SymmetricDifference	Returns elements present in either array but not both. Blueprint typed variants available.

Function	Description
Sorting
Sort	Sorts using a custom comparator function. C++ only. Blueprint typed variants (Int32, Float, String) sort by ESortDirection.
SortBy	Sorts by a key selector with Ascending or Descending direction. C++ only.

Function	Description
Utility
Shuffle	Returns a randomly reordered copy of the array using a Fisher-Yates pass. Blueprint typed variants available.
Sample	Returns N randomly selected elements. Internally shuffles then takes. Blueprint typed variants available.
Partition	Splits the array into two by predicate — matching elements first, non-matching second — returned as a TPair. C++ only.
Zip	Combines two arrays element-wise into a TArray<TPair<T, U>>. Length is clamped to the shorter array. C++ only.
Extract	Plucks a single member field from every element using a member pointer, returning a TArray of that field type. C++ only.
ExtractPtr	Same as Extract but operates on pointer arrays with a null check, returning a TSet. C++ only.
ExtractWith	Plucks a field using a lambda extractor instead of a member pointer, for cases where the field isn't directly accessible. C++ only.

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