Enumerable.ElementAt Method

Definition

Namespace:

System.Linq

Assembly:

System.Linq.dll

Overloads

ElementAt<TSource>(IEnumerable<TSource>, Index)	Returns the element at a specified index in a sequence.
ElementAt<TSource>(IEnumerable<TSource>, Int32)	Returns the element at a specified index in a sequence.

ElementAt<TSource>(IEnumerable<TSource>, Index)

Source:

ElementAt.cs

Returns the element at a specified index in a sequence.

public:
generic <typename TSource>
[System::Runtime::CompilerServices::Extension]
 static TSource ElementAt(System::Collections::Generic::IEnumerable<TSource> ^ source, Index index);

public static TSource ElementAt<TSource> (this System.Collections.Generic.IEnumerable<TSource> source, Index index);

static member ElementAt : seq<'Source> * Index -> 'Source

<Extension()>
Public Function ElementAt(Of TSource) (source As IEnumerable(Of TSource), index As Index) As TSource

Type Parameters

TSource

The type of the elements of source.

Parameters

source

IEnumerable<TSource>

An IEnumerable<T> to return an element from.

index

Index

The index of the element to retrieve, which is either from the beginning or the end of the sequence.

Returns

TSource

The element at the specified position in the source sequence.

Exceptions

ArgumentNullException

source is null.

ArgumentOutOfRangeException

index is outside the bounds of the source sequence.

Remarks

If the type of source implements IList<T>, that implementation is used to obtain the element at the specified index. Otherwise, this method obtains the specified element.

This method throws an exception if index is out of range. To instead return a default value when the specified index is out of range, use the ElementAtOrDefault method.

ElementAt<TSource>(IEnumerable<TSource>, Int32)

Source:

ElementAt.cs

Returns the element at a specified index in a sequence.

public:
generic <typename TSource>
[System::Runtime::CompilerServices::Extension]
 static TSource ElementAt(System::Collections::Generic::IEnumerable<TSource> ^ source, int index);

public static TSource ElementAt<TSource> (this System.Collections.Generic.IEnumerable<TSource> source, int index);

static member ElementAt : seq<'Source> * int -> 'Source

<Extension()>
Public Function ElementAt(Of TSource) (source As IEnumerable(Of TSource), index As Integer) As TSource

Type Parameters

TSource

The type of the elements of source.

Parameters

source

IEnumerable<TSource>

An IEnumerable<T> to return an element from.

index

Int32

The zero-based index of the element to retrieve.

Returns

TSource

The element at the specified position in the source sequence.

Exceptions

ArgumentNullException

source is null.

ArgumentOutOfRangeException

index is less than 0 or greater than or equal to the number of elements in source.

Examples

The following code example demonstrates how to use ElementAt to return an element at a specific position.

string[] names =
    { "Hartono, Tommy", "Adams, Terry", "Andersen, Henriette Thaulow",

        "Hedlund, Magnus", "Ito, Shu" };
Random random = new Random(DateTime.Now.Millisecond);

string name = names.ElementAt(random.Next(0, names.Length));

Console.WriteLine("The name chosen at random is '{0}'.", name);

/*
 This code produces output similar to the following:

 The name chosen at random is 'Ito, Shu'.
*/

' Create an array of strings.
Dim names() As String =
{"Hartono, Tommy", "Adams, Terry", "Andersen, Henriette Thaulow", "Hedlund, Magnus", "Ito, Shu"}

Dim random As Random = New Random(DateTime.Now.Millisecond)

' Get a string at a random index within the array.
Dim name As String = names.ElementAt(random.Next(0, names.Length))

' Display the output.
Console.WriteLine($"The name chosen at random is {name}")

' This code produces output similar to the following:
'
' The name chosen at random is Ito, Shu

Remarks

If the type of source implements IList<T>, that implementation is used to obtain the element at the specified index. Otherwise, this method obtains the specified element.

This method throws an exception if index is out of range. To instead return a default value when the specified index is out of range, use the ElementAtOrDefault method.