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> Unreal Engine API Reference > Runtime > Core > Containers > TArrayView

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TArrayView

Templated fixed-size view of another array

Inheritance Hierarchy

TArrayView

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References

Module	Core
Header	/Engine/Source/Runtime/Core/Public/Containers/ArrayView.h
Include	#include "Containers/ArrayView.h"

Syntax

template<typename InElementType, typename InSizeType>
class TArrayView

Remarks

Templated fixed-size view of another array

A statically sized view of an array of typed elements. Designed to allow functions to take either a fixed C array or a TArray with an arbitrary allocator as an argument when the function neither adds nor removes elements

e.g.: int32 SumAll(TArrayView<const int32> array) { return Algo::Accumulate(array); }

could be called as: SumAll(MyTArray);\ SumAll(MyCArray); SumAll(MakeArrayView(Ptr, Num));

auto Values = { 1, 2, 3 }; SumAll(Values);

Note: View classes are not const-propagating! If you want a view where the elements are const, you need "TArrayView<const T>" not "const TArrayView<T>"!

Caution: Treat a view like a reference to the elements in the array. DO NOT free or reallocate the array while the view exists! For this reason, be mindful of lifetimes when constructing TArrayViews from rvalue initializer lists:

TArrayView<int> View = { 1, 2, 3 }; // construction of array view from rvalue initializer list int n = View[0]; // undefined behavior, as the initializer list was destroyed at the end of the previous line

Constructors

	Name	Description
	TArrayView()	Constructor.
	TArrayView ( OtherRangeType&& Other )	Constructor from another range
	TArrayView ( OtherRangeType&& Other )
	TArrayView ( std::initializer_list< ElementType ... )	Construct a view of an initializer list.
	TArrayView ( OtherElementType* InData, SizeType InCount )	Construct a view of an arbitrary pointer

Functions

	Name	Description
ElementType ...	begin()	DO NOT USE DIRECTLY STL-like iterators to enable range-based for loop support.
void	CheckInvariants()	Checks array invariants: if array size is greater than or equal to zero.
bool	Contains ( const ComparisonType& Item )	Checks if this array contains the element.
bool	ContainsByPredicate ( Predicate Pred )	Checks if this array contains an element for which the predicate is true.
ElementType ...	end()
TArray< type...	FilterByPredicate ( Predicate Pred )	Filters the elements in the array based on a predicate functor.
bool	Find ( const ElementType& Item, SizeType& Index )	Finds element within the array.
SizeType	Find ( const ElementType& Item )	Finds element within the array.
ElementType ...	FindByKey ( const KeyType& Key )	Finds an item by key (assuming the ElementType overloads operator== for the comparison).
ElementType ...	FindByPredicate ( Predicate Pred )	Finds an element which matches a predicate functor.
bool	FindLast ( const ElementType& Item, SizeType& Index )	Finds element within the array starting from the end.
SizeType	FindLastByPredicate ( Predicate Pred )	Finds element within the array starting from the end. Uses predicate to match element.
SizeType	FindLastByPredicate ( Predicate Pred, SizeType StartIndex )	Finds element within the array starting from StartIndex and going backwards.
ElementType ...	GetData()	Helper function for returning a typed pointer to the first array entry.
constexpr si...	GetTypeAlignment()	Helper function returning the alignment of the inner type.
constexpr si...	GetTypeSize()	Helper function returning the size of the inner type.
SizeType	IndexOfByKey ( const KeyType& Key )	Finds an item by key (assuming the ElementType overloads operator== for the comparison).
SizeType	IndexOfByPredicate ( Predicate Pred )	Finds an item by predicate.
bool	IsEmpty()	Returns true if the array view is empty and contains no elements.
bool	IsValidIndex ( SizeType Index )	Tests if index is valid, i.e. greater than or equal to zero, and less than the number of elements in the array.
ElementType ...	Last ( SizeType IndexFromTheEnd )	Returns n-th last element from the array.
TArrayView	Left ( SizeType Count )	Returns the left-most part of the view by taking the given number of elements from the left.
TArrayView	LeftChop ( SizeType Count )	Returns the left-most part of the view by chopping the given number of elements from the right.
void	LeftChopInline ( SizeType CharCount )	Modifies the view by chopping the given number of elements from the right.
void	LeftInline ( SizeType CharCount )	Modifies the view to be the given number of elements from the left.
TArrayView	Mid ( SizeType Index, SizeType Count )	Returns the middle part of the view by taking up to the given number of elements from the given position.
void	MidInline ( SizeType Position, SizeType CharCount )	Modifies the view to be the middle part by taking up to the given number of elements from the given position.
SizeType	Num()	Returns number of elements in array.
void	RangeCheck ( SizeType Index )	Checks if index is in array range.
TArrayView	Right ( SizeType Count )	Returns the right-most part of the view by taking the given number of elements from the right.
TArrayView	RightChop ( SizeType Count )	Returns the right-most part of the view by chopping the given number of elements from the left.
void	RightChopInline ( SizeType CharCount )	Modifies the view by chopping the given number of elements from the left.
void	RightInline ( SizeType CharCount )	Modifies the view to be the given number of elements from the right.
TArrayView	Slice ( SizeType Index, SizeType InNum )	Returns a sliced view This is similar to Mid(), but with a narrow contract, i.e. slicing outside of the range of the view is illegal.
void	SliceRangeCheck ( SizeType Index, SizeType InNum )	Checks if a slice range [Index, Index+InNum) is in array range.
void	Sort()	Sorts the array assuming < operator is defined for the item type.
void	Sort ( const PREDICATE_CLASS& Predicate )	Sorts the array using user define predicate class.
void	StableSort()	Stable sorts the array assuming < operator is defined for the item type.
void	StableSort ( const PREDICATE_CLASS& Predicate )	Stable sorts the array using user defined predicate class.

Operators

		Name	Description
	ElementType ...	operator[] ( SizeType Index )	Array bracket operator. Returns reference to element at given index.

Typedefs

Name	Description
ElementType
SizeType
TIsCompatibleElementType
TIsCompatibleRangeType
TIsReinterpretableRangeType

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