ArraySegment<T> Struct

Reference

Definition

Namespace:: System

Assembly:: System.Runtime.dll

Assembly:: mscorlib.dll

Assembly:: netstandard.dll

Source:: ArraySegment.cs

Source:: ArraySegment.cs

Source:: ArraySegment.cs

Important

Some information relates to prerelease product that may be substantially modified before it’s released. Microsoft makes no warranties, express or implied, with respect to the information provided here.

Delimits a section of a one-dimensional array.

generic <typename T>
public value class ArraySegment : System::Collections::Generic::ICollection<T>, System::Collections::Generic::IEnumerable<T>, System::Collections::Generic::IList<T>, System::Collections::Generic::IReadOnlyCollection<T>, System::Collections::Generic::IReadOnlyList<T>

generic <typename T>
public value class ArraySegment

public struct ArraySegment<T> : System.Collections.Generic.ICollection<T>, System.Collections.Generic.IEnumerable<T>, System.Collections.Generic.IList<T>, System.Collections.Generic.IReadOnlyCollection<T>, System.Collections.Generic.IReadOnlyList<T>

public readonly struct ArraySegment<T> : System.Collections.Generic.ICollection<T>, System.Collections.Generic.IEnumerable<T>, System.Collections.Generic.IList<T>, System.Collections.Generic.IReadOnlyCollection<T>, System.Collections.Generic.IReadOnlyList<T>

[System.Serializable]
public struct ArraySegment<T>

[System.Serializable]
public struct ArraySegment<T> : System.Collections.Generic.ICollection<T>, System.Collections.Generic.IEnumerable<T>, System.Collections.Generic.IList<T>, System.Collections.Generic.IReadOnlyCollection<T>, System.Collections.Generic.IReadOnlyList<T>

type ArraySegment<'T> = struct
    interface ICollection<'T>
    interface seq<'T>
    interface IEnumerable
    interface IList<'T>
    interface IReadOnlyCollection<'T>
    interface IReadOnlyList<'T>

[<System.Serializable>]
type ArraySegment<'T> = struct

[<System.Serializable>]
type ArraySegment<'T> = struct
    interface IList<'T>
    interface ICollection<'T>
    interface IReadOnlyList<'T>
    interface IReadOnlyCollection<'T>
    interface seq<'T>
    interface IEnumerable

[<System.Serializable>]
type ArraySegment<'T> = struct
    interface IList<'T>
    interface ICollection<'T>
    interface seq<'T>
    interface IEnumerable
    interface IReadOnlyList<'T>
    interface IReadOnlyCollection<'T>

type ArraySegment<'T> = struct
    interface IList<'T>
    interface ICollection<'T>
    interface IReadOnlyList<'T>
    interface IReadOnlyCollection<'T>
    interface seq<'T>
    interface IEnumerable

Public Structure ArraySegment(Of T)
Implements ICollection(Of T), IEnumerable(Of T), IList(Of T), IReadOnlyCollection(Of T), IReadOnlyList(Of T)

Public Structure ArraySegment(Of T)

Type Parameters

T

The type of the elements in the array segment.

Inheritance: Object

ValueType
ArraySegment<T>

Attributes: SerializableAttribute

Implements: ICollection<T> IEnumerable<T> IList<T> IReadOnlyCollection<T> IReadOnlyList<T> IEnumerable

Examples

The following code example passes an ArraySegment<T> structure to a method.

using namespace System;


namespace Sample
{
    public ref class SampleArray  
    {
    public:
        static void Work()  
        {

            // Create and initialize a new string array.
            array <String^>^ words = {"The", "quick", "brown",
                "fox", "jumps", "over", "the", "lazy", "dog"};

            // Display the initial contents of the array.
            Console::WriteLine("The first array segment"
                " (with all the array's elements) contains:");
            PrintIndexAndValues(words);

            // Define an array segment that contains the entire array.
            ArraySegment<String^> segment(words);
            
            // Display the contents of the ArraySegment.
            Console::WriteLine("The first array segment"
                " (with all the array's elements) contains:");
            PrintIndexAndValues(segment);

            // Define an array segment that contains the middle five 
            // values of the array.
            ArraySegment<String^> middle(words, 2, 5);
            
            // Display the contents of the ArraySegment.
            Console::WriteLine("The second array segment"
                " (with the middle five elements) contains:");
            PrintIndexAndValues(middle);

            // Modify the fourth element of the first array 
            // segment
            segment.Array[3] = "LION";

            // Display the contents of the second array segment 
            // middle. Note that the value of its second element 
            // also changed.
            Console::WriteLine("After the first array segment"
                " is modified,the second array segment"
                " now contains:");
            PrintIndexAndValues(middle);
            Console::ReadLine();
        }

        static void PrintIndexAndValues(ArraySegment<String^>^ segment)  
        {
            for (int i = segment->Offset; 
                i < (segment->Offset + segment->Count); i++)  
            {
                Console::WriteLine("   [{0}] : {1}", i,
                    segment->Array[i]);
            }
            Console::WriteLine();
        }

        static void PrintIndexAndValues(array<String^>^ words) 
        {
            for (int i = 0; i < words->Length; i++)  
            {
                Console::WriteLine("   [{0}] : {1}", i,
                    words[i]);
            }
            Console::WriteLine();
        }
    };
}

int main()
{
    Sample::SampleArray::Work();
    return 0; 
}


    /* 
    This code produces the following output.

    The original array initially contains:
    [0] : The
    [1] : quick
    [2] : brown
    [3] : fox
    [4] : jumps
    [5] : over
    [6] : the
    [7] : lazy
    [8] : dog

    The first array segment (with all the array's elements) contains:
    [0] : The
    [1] : quick
    [2] : brown
    [3] : fox
    [4] : jumps
    [5] : over
    [6] : the
    [7] : lazy
    [8] : dog

    The second array segment (with the middle five elements) contains:
    [2] : brown
    [3] : fox
    [4] : jumps
    [5] : over
    [6] : the

    After the first array segment is modified, the second array segment now contains:
    [2] : brown
    [3] : LION
    [4] : jumps
    [5] : over
    [6] : the

    */

using System;

public class SamplesArray  {

   public static void Main()  {

      // Create and initialize a new string array.
      String[] myArr = { "The", "quick", "brown", "fox", "jumps", "over", "the", "lazy", "dog" };

      // Display the initial contents of the array.
      Console.WriteLine( "The original array initially contains:" );
      PrintIndexAndValues( myArr );

      // Define an array segment that contains the entire array.
      ArraySegment<string> myArrSegAll = new ArraySegment<string>( myArr );

      // Display the contents of the ArraySegment.
      Console.WriteLine( "The first array segment (with all the array's elements) contains:" );
      PrintIndexAndValues( myArrSegAll );

      // Define an array segment that contains the middle five values of the array.
      ArraySegment<string> myArrSegMid = new ArraySegment<string>( myArr, 2, 5 );

      // Display the contents of the ArraySegment.
      Console.WriteLine( "The second array segment (with the middle five elements) contains:" );
      PrintIndexAndValues( myArrSegMid );

      // Modify the fourth element of the first array segment myArrSegAll.
      myArrSegAll.Array[3] = "LION";

      // Display the contents of the second array segment myArrSegMid.
      // Note that the value of its second element also changed.
      Console.WriteLine( "After the first array segment is modified, the second array segment now contains:" );
      PrintIndexAndValues( myArrSegMid );
   }

   public static void PrintIndexAndValues( ArraySegment<string> arrSeg )  {
      for ( int i = arrSeg.Offset; i < (arrSeg.Offset + arrSeg.Count); i++ )  {
         Console.WriteLine( "   [{0}] : {1}", i, arrSeg.Array[i] );
      }
      Console.WriteLine();
   }

   public static void PrintIndexAndValues( String[] myArr )  {
      for ( int i = 0; i < myArr.Length; i++ )  {
         Console.WriteLine( "   [{0}] : {1}", i, myArr[i] );
      }
      Console.WriteLine();
   }
}


/*
This code produces the following output.

The original array initially contains:
   [0] : The
   [1] : quick
   [2] : brown
   [3] : fox
   [4] : jumps
   [5] : over
   [6] : the
   [7] : lazy
   [8] : dog

The first array segment (with all the array's elements) contains:
   [0] : The
   [1] : quick
   [2] : brown
   [3] : fox
   [4] : jumps
   [5] : over
   [6] : the
   [7] : lazy
   [8] : dog

The second array segment (with the middle five elements) contains:
   [2] : brown
   [3] : fox
   [4] : jumps
   [5] : over
   [6] : the

After the first array segment is modified, the second array segment now contains:
   [2] : brown
   [3] : LION
   [4] : jumps
   [5] : over
   [6] : the

*/

open System

// Print functions.
let printIndexAndValues (myArr: string []) =
    for i = 0 to myArr.Length - 1 do
        printfn $"   [{i}] : {myArr[i]}"
    printfn ""

let printIndexAndValuesSeg (arrSeg: ArraySegment<string>) =
    for i = arrSeg.Offset to arrSeg.Offset + arrSeg.Count - 1 do
        printfn $"   [{i}] : {arrSeg.Array[i]}"
    printfn ""

// Create and initialize a new string array.
let myArr = [| "The"; "quick"; "brown"; "fox"; "jumps"; "over"; "the"; "lazy"; "dog" |]

// Display the initial contents of the array.
printfn "The original array initially contains:"
printIndexAndValues myArr

// Define an array segment that contains the entire array.
let myArrSegAll = ArraySegment<string>(myArr)

// Display the contents of the ArraySegment.
printfn "The first array segment (with all the array's elements) contains:"
printIndexAndValuesSeg myArrSegAll

// Define an array segment that contains the middle five values of the array.
let myArrSegMid = ArraySegment<string>(myArr, 2, 5)

// Display the contents of the ArraySegment.
printfn "The second array segment (with the middle five elements) contains:"
printIndexAndValuesSeg myArrSegMid

// Modify the fourth element of the first array segment myArrSegAll.
myArrSegAll.Array[3] <- "LION"

// Display the contents of the second array segment myArrSegMid.
// Note that the value of its second element also changed.
printfn "After the first array segment is modified, the second array segment now contains:"
printIndexAndValuesSeg myArrSegMid


(*
This code produces the following output.

The original array initially contains:
   [0] : The
   [1] : quick
   [2] : brown
   [3] : fox
   [4] : jumps
   [5] : over
   [6] : the
   [7] : lazy
   [8] : dog

The first array segment (with all the array's elements) contains:
   [0] : The
   [1] : quick
   [2] : brown
   [3] : fox
   [4] : jumps
   [5] : over
   [6] : the
   [7] : lazy
   [8] : dog

The second array segment (with the middle five elements) contains:
   [2] : brown
   [3] : fox
   [4] : jumps
   [5] : over
   [6] : the

After the first array segment is modified, the second array segment now contains:
   [2] : brown
   [3] : LION
   [4] : jumps
   [5] : over
   [6] : the

*)

Public Class SamplesArray

    Public Shared Sub Main()

        ' Create and initialize a new string array.
        Dim myArr As String() =  {"The", "quick", "brown", "fox", "jumps", "over", "the", "lazy", "dog"}

        ' Display the initial contents of the array.
        Console.WriteLine("The original array initially contains:")
        PrintIndexAndValues(myArr)

        ' Define an array segment that contains the entire array.
        Dim myArrSegAll As New ArraySegment(Of String)(myArr)

        ' Display the contents of the ArraySegment.
        Console.WriteLine("The first array segment (with all the array's elements) contains:")
        PrintIndexAndValues(myArrSegAll)

        ' Define an array segment that contains the middle five values of the array.
        Dim myArrSegMid As New ArraySegment(Of String)(myArr, 2, 5)

        ' Display the contents of the ArraySegment.
        Console.WriteLine("The second array segment (with the middle five elements) contains:")
        PrintIndexAndValues(myArrSegMid)

        ' Modify the fourth element of the first array segment myArrSegAll.
        myArrSegAll.Array(3) = "LION"

        ' Display the contents of the second array segment myArrSegMid.
        ' Note that the value of its second element also changed.
        Console.WriteLine("After the first array segment is modified, the second array segment now contains:")
        PrintIndexAndValues(myArrSegMid)

    End Sub

    Public Shared Sub PrintIndexAndValues(arrSeg As ArraySegment(Of String))
        Dim i As Integer
        For i = arrSeg.Offset To (arrSeg.Offset + arrSeg.Count - 1)
            Console.WriteLine("   [{0}] : {1}", i, arrSeg.Array(i))
        Next i
        Console.WriteLine()
    End Sub

    Public Shared Sub PrintIndexAndValues(myArr as String())
        Dim i As Integer
        For i = 0 To (myArr.Length - 1)
            Console.WriteLine("   [{0}] : {1}", i, myArr(i))
        Next i
        Console.WriteLine()
    End Sub

End Class


'This code produces the following output.
'
'The original array initially contains:
'   [0] : The
'   [1] : quick
'   [2] : brown
'   [3] : fox
'   [4] : jumps
'   [5] : over
'   [6] : the
'   [7] : lazy
'   [8] : dog
'
'The first array segment (with all the array's elements) contains:
'   [0] : The
'   [1] : quick
'   [2] : brown
'   [3] : fox
'   [4] : jumps
'   [5] : over
'   [6] : the
'   [7] : lazy
'   [8] : dog
'
'The second array segment (with the middle five elements) contains:
'   [2] : brown
'   [3] : fox
'   [4] : jumps
'   [5] : over
'   [6] : the
'
'After the first array segment is modified, the second array segment now contains:
'   [2] : brown
'   [3] : LION
'   [4] : jumps
'   [5] : over
'   [6] : the

Remarks

ArraySegment<T> is a wrapper around an array that delimits a range of elements in that array. Multiple ArraySegment<T> instances can refer to the same original array and can overlap. The original array must be one-dimensional and must have zero-based indexing.

Note

ArraySegment<T> implements the IReadOnlyCollection<T> interface starting with the .NET Framework 4.6; in previous versions of the .NET Framework, the ArraySegment<T> structure did not implement this interface.

The ArraySegment<T> structure is useful whenever the elements of an array will be manipulated in distinct segments. For example:

You can pass an ArraySegment<T> object that represents only a portion of an array as an argument to a method, rather than call a relatively expensive method like Copy to pass a copy of a portion of an array.
In a multithreaded app, you can use the ArraySegment<T> structure to have each thread operate on only a portion of the array.

For task-based asynchronous operations, you can use an ArraySegment<T> object to ensure that each task operates on a distinct segment of the array. The following example divides an array into individual segments with up to ten elements. Each element in the segment is multiplied by its segment number. The result shows that using the ArraySegment<T> class to manipulate elements in this way changes the values of its underlying array.

using System;
using System.Collections.Generic;
using System.Threading.Tasks;

public class Example
{
   private const int segmentSize = 10;

   public static async Task Main()
   {
      List<Task> tasks = new List<Task>();

      // Create array.
      int[] arr = new int[50];
      for (int ctr = 0; ctr <= arr.GetUpperBound(0); ctr++)
         arr[ctr] = ctr + 1;

      // Handle array in segments of 10.
      for (int ctr = 1; ctr <= Math.Ceiling(((double)arr.Length)/segmentSize); ctr++) {
         int multiplier = ctr;
         int elements = (multiplier - 1) * 10 + segmentSize > arr.Length ?
                         arr.Length - (multiplier - 1) * 10 : segmentSize;
         ArraySegment<int> segment = new ArraySegment<int>(arr, (ctr - 1) * 10, elements);
         tasks.Add(Task.Run( () => { IList<int> list = (IList<int>) segment;
                                     for (int index = 0; index < list.Count; index++)
                                        list[index] = list[index] * multiplier;
                                   } ));
      }
      try {
         await Task.WhenAll(tasks.ToArray());
         int elementsShown = 0;
         foreach (var value in arr) {
            Console.Write("{0,3} ", value);
            elementsShown++;
            if (elementsShown % 18 == 0)
               Console.WriteLine();
         }
      }
      catch (AggregateException e) {
         Console.WriteLine("Errors occurred when working with the array:");
         foreach (var inner in e.InnerExceptions)
            Console.WriteLine("{0}: {1}", inner.GetType().Name, inner.Message);
      }
   }
}
// The example displays the following output:
//      1   2   3   4   5   6   7   8   9  10  22  24  26  28  30  32  34  36
//     38  40  63  66  69  72  75  78  81  84  87  90 124 128 132 136 140 144
//    148 152 156 160 205 210 215 220 225 230 235 240 245 250

open System
open System.Threading.Tasks

// Create array.
let arr = Array.init 50 (fun i -> i + 1)

// Handle array in segments of 10.
let tasks =
    Array.chunkBySize 10 arr
    |> Array.mapi (fun m elements ->
        let mutable segment = ArraySegment<int>(arr, m * 10, elements.Length)
        task {
            for i = 0 to segment.Count - 1 do
                segment[i] <- segment[i] * (m + 1)
        } :> Task)

try
    Task.WhenAll(tasks).Wait()
    let mutable i = 0

    for value in arr do
        printf $"{value, 3} "
        i <- i + 1
        if i % 18 = 0 then printfn ""

with :? AggregateException as e ->
    printfn "Errors occurred when working with the array:"

    for inner in e.InnerExceptions do
        printfn $"{inner.GetType().Name}: {inner.Message}"


// The example displays the following output:
//      1   2   3   4   5   6   7   8   9  10  22  24  26  28  30  32  34  36
//     38  40  63  66  69  72  75  78  81  84  87  90 124 128 132 136 140 144
//    148 152 156 160 205 210 215 220 225 230 235 240 245 250

Imports System.Collections.Generic
Imports System.Threading.Tasks

Module Example
  Private Const SegmentSize As Integer = 10
  
   Public Sub Main()
      Dim tasks As New List(Of Task)
      
       ' Create array.
      Dim arr(49) As Integer
      For ctr As Integer = 0 To arr.GetUpperBound(0)
         arr(ctr) = ctr + 1
      Next

      ' Handle array in segments of 10.
      For ctr As Integer = 1 To CInt(Math.Ceiling(arr.Length / segmentSize))
         Dim multiplier As Integer = ctr
         Dim elements As Integer = If((multiplier - 1) * 10 + segmentSize > arr.Length,
                                      arr.Length - (multiplier - 1) * 10,
                                      segmentSize)
         Dim segment As New ArraySegment(Of Integer)(arr, (ctr - 1) * 10, elements)
         tasks.Add(Task.Run( Sub()
                                Dim list As IList(Of Integer) = CType(segment, IList(Of Integer))
                                For index As Integer = 0 To list.Count - 1
                                   list(index) = list(index) * multiplier
                                Next
                             End Sub ))
      Next
      Try
         Task.WaitAll(tasks.ToArray())
         Dim elementsShown As Integer = 0
         For Each value In arr
            Console.Write("{0,3} ", value)
            elementsShown += 1
            If elementsShown Mod 18 = 0 Then Console.WriteLine()
         Next
      Catch e As AggregateException
         Console.WriteLine("Errors occurred when working with the array:")
         For Each inner As Exception In e.InnerExceptions
            Console.WriteLine("{0}: {1}", inner.GetType().Name, inner.Message)
         Next
      End Try
   End Sub
End Module
' The example displays the following output:
'         1   2   3   4   5   6   7   8   9  10  22  24  26  28  30  32  34  36
'        38  40  63  66  69  72  75  78  81  84  87  90 124 128 132 136 140 144
'       148 152 156 160 205 210 215 220 225 230 235 240 245 250

Note, however, that although the ArraySegment<T> structure can be used to divide an array into distinct segments, the segments are not completely independent of one another. The Array property returns the entire original array, not a copy of the array; therefore, changes made to the array returned by the Array property are made to the original array. If this is undesirable, you should perform operations on a copy of the array, rather than an ArraySegment<T> object that represents a portion of the array.

The Equals method and the equality and inequality operators test for reference equality when they compare two ArraySegment<T> objects. For two ArraySegment<T> objects to be considered equal, they must meet all of the following conditions:

Reference the same array.
Begin at the same index in the array.
Have the same number of elements.

If you want to retrieve an element by its index in the ArraySegment<T> object, you must cast it to an IList<T> object and retrieve it or modify it by using the IList<T>.Item[] property. Note that this is not necessary in F#. The following example retrieves the element in an ArraySegment<T> object that delimits a section of a string array.

using System;
using System.Collections.Generic;

public class Example
{
   public static void Main()
   {
      String[] names = { "Adam", "Bruce", "Charles", "Daniel",
                         "Ebenezer", "Francis", "Gilbert",
                         "Henry", "Irving", "John", "Karl",
                         "Lucian", "Michael" };
      var partNames = new ArraySegment<string>(names, 2, 5);

      // Cast the ArraySegment object to an IList<string> and enumerate it.
      var list = (IList<string>) partNames;
      for (int ctr = 0; ctr <= list.Count - 1; ctr++)
         Console.WriteLine(list[ctr]);
   }
}
// The example displays the following output:
//    Charles
//    Daniel
//    Ebenezer
//    Francis
//    Gilbert

open System

let names = 
    [| "Adam"; "Bruce"; "Charles"; "Daniel"
       "Ebenezer"; "Francis"; "Gilbert"
       "Henry"; "Irving"; "John"; "Karl"
       "Lucian"; "Michael" |]

let partNames = ArraySegment<string>(names, 2, 5)

// Enumerate over the ArraySegment object.
for part in partNames do 
    printfn $"{part}"

// The example displays the following output:
//    Charles
//    Daniel
//    Ebenezer
//    Francis
//    Gilbert

Imports System.Collections.Generic

Module Example
   Public Sub Main()
      Dim names() As String = { "Adam", "Bruce", "Charles", "Daniel", 
                                "Ebenezer", "Francis", "Gilbert", 
                                "Henry", "Irving", "John", "Karl",
                                "Lucian", "Michael" }
      Dim partNames As New ArraySegment(Of String)(names, 2, 5)
      
      ' Cast the ArraySegment object to an IList<String> and enumerate it.
      Dim list = CType(partNames, IList(Of String))
      For ctr As Integer = 0 To list.Count - 1
         Console.WriteLine(list(ctr))
      Next     
   End Sub
End Module
' The example displays the following output:
'    Charles
'    Daniel
'    Ebenezer
'    Francis
'    Gilbert

Constructors

ArraySegment<T>(T[], Int32, Int32)	Initializes a new instance of the ArraySegment<T> structure that delimits the specified range of the elements in the specified array.
ArraySegment<T>(T[])	Initializes a new instance of the ArraySegment<T> structure that delimits all the elements in the specified array.

Properties

Array	Gets the original array containing the range of elements that the array segment delimits.
Count	Gets the number of elements in the range delimited by the array segment.
Empty	Represents the empty array segment. This field is read-only.
Item[Int32]	Gets or sets the element at the specified index.
Offset	Gets the position of the first element in the range delimited by the array segment, relative to the start of the original array.

Methods

CopyTo(ArraySegment<T>)	Copies the contents of this instance into the specified destination array segment of the same type `T`.
CopyTo(T[], Int32)	Copies the contents of this instance into the specified destination array of the same type `T`, starting at the specified destination index.
CopyTo(T[])	Copies the contents of this instance into the specified destination array of the same type `T`.
Equals(ArraySegment<T>)	Determines whether the specified ArraySegment<T> structure is equal to the current instance.
Equals(Object)	Determines whether the specified object is equal to the current instance.
GetEnumerator()	Returns an enumerator that can be used to iterate through the array segment.
GetHashCode()	Returns the hash code for the current instance.
Slice(Int32, Int32)	Forms a slice of the specified length out of the current array segment starting at the specified index.
Slice(Int32)	Forms a slice out of the current array segment starting at the specified index.
ToArray()	Copies the contents of this array segment into a new array.

Operators

Equality(ArraySegment<T>, ArraySegment<T>)	Indicates whether two ArraySegment<T> structures are equal.
Implicit(T[] to ArraySegment<T>)	Defines an implicit conversion of an array of type `T` to an array segment of type `T`.
Inequality(ArraySegment<T>, ArraySegment<T>)	Indicates whether two ArraySegment<T> structures are unequal.

Explicit Interface Implementations

ICollection<T>.Add(T)	Throws a NotSupportedException exception in all cases.
ICollection<T>.Clear()	Throws a NotSupportedException exception in all cases.
ICollection<T>.Contains(T)	Determines whether the array segment contains a specific value.
ICollection<T>.CopyTo(T[], Int32)	Copies the elements of the array segment to an array, starting at the specified array index.
ICollection<T>.IsReadOnly	Gets a value that indicates whether the array segment is read-only.
ICollection<T>.Remove(T)	Throws a NotSupportedException exception in all cases.
IEnumerable.GetEnumerator()	Returns an enumerator that iterates through an array segment.
IEnumerable<T>.GetEnumerator()	Returns an enumerator that iterates through the array segment.
IList<T>.IndexOf(T)	Determines the index of a specific item in the array segment.
IList<T>.Insert(Int32, T)	Throws a NotSupportedException exception in all cases.
IList<T>.Item[Int32]	Gets or sets the element at the specified index.
IList<T>.RemoveAt(Int32)	Throws a NotSupportedException exception in all cases.
IReadOnlyList<T>.Item[Int32]	Gets the element at the specified index of the array segment.

Extension Methods

ToFrozenDictionary<TSource,TKey>(IEnumerable<TSource>, Func<TSource,TKey>, IEqualityComparer<TKey>)	Creates a FrozenDictionary<TKey,TValue> from an IEnumerable<T> according to specified key selector function.
ToFrozenDictionary<TSource,TKey,TElement>(IEnumerable<TSource>, Func<TSource,TKey>, Func<TSource,TElement>, IEqualityComparer<TKey>)	Creates a FrozenDictionary<TKey,TValue> from an IEnumerable<T> according to specified key selector and element selector functions.
ToFrozenSet<T>(IEnumerable<T>, IEqualityComparer<T>)	Creates a FrozenSet<T> with the specified values.
AsReadOnly<T>(IList<T>)	Returns a read-only ReadOnlyCollection<T> wrapper for the specified list.
ToImmutableArray<TSource>(IEnumerable<TSource>)	Creates an immutable array from the specified collection.
ToImmutableDictionary<TSource,TKey>(IEnumerable<TSource>, Func<TSource,TKey>, IEqualityComparer<TKey>)	Constructs an immutable dictionary based on some transformation of a sequence.
ToImmutableDictionary<TSource,TKey>(IEnumerable<TSource>, Func<TSource,TKey>)	Constructs an immutable dictionary from an existing collection of elements, applying a transformation function to the source keys.
ToImmutableDictionary<TSource,TKey,TValue>(IEnumerable<TSource>, Func<TSource,TKey>, Func<TSource,TValue>, IEqualityComparer<TKey>, IEqualityComparer<TValue>)	Enumerates and transforms a sequence, and produces an immutable dictionary of its contents by using the specified key and value comparers.
ToImmutableDictionary<TSource,TKey,TValue>(IEnumerable<TSource>, Func<TSource,TKey>, Func<TSource,TValue>, IEqualityComparer<TKey>)	Enumerates and transforms a sequence, and produces an immutable dictionary of its contents by using the specified key comparer.
ToImmutableDictionary<TSource,TKey,TValue>(IEnumerable<TSource>, Func<TSource,TKey>, Func<TSource,TValue>)	Enumerates and transforms a sequence, and produces an immutable dictionary of its contents.
ToImmutableHashSet<TSource>(IEnumerable<TSource>, IEqualityComparer<TSource>)	Enumerates a sequence, produces an immutable hash set of its contents, and uses the specified equality comparer for the set type.
ToImmutableHashSet<TSource>(IEnumerable<TSource>)	Enumerates a sequence and produces an immutable hash set of its contents.
ToImmutableList<TSource>(IEnumerable<TSource>)	Enumerates a sequence and produces an immutable list of its contents.
ToImmutableSortedDictionary<TSource,TKey,TValue>(IEnumerable<TSource>, Func<TSource,TKey>, Func<TSource,TValue>, IComparer<TKey>, IEqualityComparer<TValue>)	Enumerates and transforms a sequence, and produces an immutable sorted dictionary of its contents by using the specified key and value comparers.
ToImmutableSortedDictionary<TSource,TKey,TValue>(IEnumerable<TSource>, Func<TSource,TKey>, Func<TSource,TValue>, IComparer<TKey>)	Enumerates and transforms a sequence, and produces an immutable sorted dictionary of its contents by using the specified key comparer.
ToImmutableSortedDictionary<TSource,TKey,TValue>(IEnumerable<TSource>, Func<TSource,TKey>, Func<TSource,TValue>)	Enumerates and transforms a sequence, and produces an immutable sorted dictionary of its contents.
ToImmutableSortedSet<TSource>(IEnumerable<TSource>, IComparer<TSource>)	Enumerates a sequence, produces an immutable sorted set of its contents, and uses the specified comparer.
ToImmutableSortedSet<TSource>(IEnumerable<TSource>)	Enumerates a sequence and produces an immutable sorted set of its contents.
CopyToDataTable<T>(IEnumerable<T>, DataTable, LoadOption, FillErrorEventHandler)	Copies DataRow objects to the specified DataTable, given an input IEnumerable<T> object where the generic parameter `T` is DataRow.
CopyToDataTable<T>(IEnumerable<T>, DataTable, LoadOption)	Copies DataRow objects to the specified DataTable, given an input IEnumerable<T> object where the generic parameter `T` is DataRow.
CopyToDataTable<T>(IEnumerable<T>)	Returns a DataTable that contains copies of the DataRow objects, given an input IEnumerable<T> object where the generic parameter `T` is DataRow.
Aggregate<TSource>(IEnumerable<TSource>, Func<TSource,TSource,TSource>)	Applies an accumulator function over a sequence.
Aggregate<TSource,TAccumulate>(IEnumerable<TSource>, TAccumulate, Func<TAccumulate,TSource,TAccumulate>)	Applies an accumulator function over a sequence. The specified seed value is used as the initial accumulator value.
Aggregate<TSource,TAccumulate,TResult>(IEnumerable<TSource>, TAccumulate, Func<TAccumulate,TSource,TAccumulate>, Func<TAccumulate,TResult>)	Applies an accumulator function over a sequence. The specified seed value is used as the initial accumulator value, and the specified function is used to select the result value.
AggregateBy<TSource,TKey,TAccumulate>(IEnumerable<TSource>, Func<TSource, TKey>, TAccumulate, Func<TAccumulate,TSource,TAccumulate>, IEqualityComparer<TKey>)	Applies an accumulator function over a sequence, grouping results by key.
AggregateBy<TSource,TKey,TAccumulate>(IEnumerable<TSource>, Func<TSource, TKey>, Func<TKey,TAccumulate>, Func<TAccumulate,TSource,TAccumulate>, IEqualityComparer<TKey>)	Applies an accumulator function over a sequence, grouping results by key.
All<TSource>(IEnumerable<TSource>, Func<TSource,Boolean>)	Determines whether all elements of a sequence satisfy a condition.
Any<TSource>(IEnumerable<TSource>, Func<TSource,Boolean>)	Determines whether any element of a sequence satisfies a condition.
Any<TSource>(IEnumerable<TSource>)	Determines whether a sequence contains any elements.
Append<TSource>(IEnumerable<TSource>, TSource)	Appends a value to the end of the sequence.
AsEnumerable<TSource>(IEnumerable<TSource>)	Returns the input typed as IEnumerable<T>.
Average<TSource>(IEnumerable<TSource>, Func<TSource,Decimal>)	Computes the average of a sequence of Decimal values that are obtained by invoking a transform function on each element of the input sequence.
Average<TSource>(IEnumerable<TSource>, Func<TSource,Double>)	Computes the average of a sequence of Double values that are obtained by invoking a transform function on each element of the input sequence.
Average<TSource>(IEnumerable<TSource>, Func<TSource,Int32>)	Computes the average of a sequence of Int32 values that are obtained by invoking a transform function on each element of the input sequence.
Average<TSource>(IEnumerable<TSource>, Func<TSource,Int64>)	Computes the average of a sequence of Int64 values that are obtained by invoking a transform function on each element of the input sequence.
Average<TSource>(IEnumerable<TSource>, Func<TSource,Nullable<Decimal>>)	Computes the average of a sequence of nullable Decimal values that are obtained by invoking a transform function on each element of the input sequence.
Average<TSource>(IEnumerable<TSource>, Func<TSource,Nullable<Double>>)	Computes the average of a sequence of nullable Double values that are obtained by invoking a transform function on each element of the input sequence.
Average<TSource>(IEnumerable<TSource>, Func<TSource,Nullable<Int32>>)	Computes the average of a sequence of nullable Int32 values that are obtained by invoking a transform function on each element of the input sequence.
Average<TSource>(IEnumerable<TSource>, Func<TSource,Nullable<Int64>>)	Computes the average of a sequence of nullable Int64 values that are obtained by invoking a transform function on each element of the input sequence.
Average<TSource>(IEnumerable<TSource>, Func<TSource,Nullable<Single>>)	Computes the average of a sequence of nullable Single values that are obtained by invoking a transform function on each element of the input sequence.
Average<TSource>(IEnumerable<TSource>, Func<TSource,Single>)	Computes the average of a sequence of Single values that are obtained by invoking a transform function on each element of the input sequence.
Cast<TResult>(IEnumerable)	Casts the elements of an IEnumerable to the specified type.
Chunk<TSource>(IEnumerable<TSource>, Int32)	Splits the elements of a sequence into chunks of size at most `size`.
Concat<TSource>(IEnumerable<TSource>, IEnumerable<TSource>)	Concatenates two sequences.
Contains<TSource>(IEnumerable<TSource>, TSource, IEqualityComparer<TSource>)	Determines whether a sequence contains a specified element by using a specified IEqualityComparer<T>.
Contains<TSource>(IEnumerable<TSource>, TSource)	Determines whether a sequence contains a specified element by using the default equality comparer.
Count<TSource>(IEnumerable<TSource>, Func<TSource,Boolean>)	Returns a number that represents how many elements in the specified sequence satisfy a condition.
Count<TSource>(IEnumerable<TSource>)	Returns the number of elements in a sequence.
CountBy<TSource,TKey>(IEnumerable<TSource>, Func<TSource,TKey>, IEqualityComparer<TKey>)	Returns the count of elements in the source sequence grouped by key.
DefaultIfEmpty<TSource>(IEnumerable<TSource>, TSource)	Returns the elements of the specified sequence or the specified value in a singleton collection if the sequence is empty.
DefaultIfEmpty<TSource>(IEnumerable<TSource>)	Returns the elements of the specified sequence or the type parameter's default value in a singleton collection if the sequence is empty.
Distinct<TSource>(IEnumerable<TSource>, IEqualityComparer<TSource>)	Returns distinct elements from a sequence by using a specified IEqualityComparer<T> to compare values.
Distinct<TSource>(IEnumerable<TSource>)	Returns distinct elements from a sequence by using the default equality comparer to compare values.
DistinctBy<TSource,TKey>(IEnumerable<TSource>, Func<TSource,TKey>, IEqualityComparer<TKey>)	Returns distinct elements from a sequence according to a specified key selector function and using a specified comparer to compare keys.
DistinctBy<TSource,TKey>(IEnumerable<TSource>, Func<TSource,TKey>)	Returns distinct elements from a sequence according to a specified key selector function.
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.
ElementAtOrDefault<TSource>(IEnumerable<TSource>, Index)	Returns the element at a specified index in a sequence or a default value if the index is out of range.
ElementAtOrDefault<TSource>(IEnumerable<TSource>, Int32)	Returns the element at a specified index in a sequence or a default value if the index is out of range.
Except<TSource>(IEnumerable<TSource>, IEnumerable<TSource>, IEqualityComparer<TSource>)	Produces the set difference of two sequences by using the specified IEqualityComparer<T> to compare values.
Except<TSource>(IEnumerable<TSource>, IEnumerable<TSource>)	Produces the set difference of two sequences by using the default equality comparer to compare values.
ExceptBy<TSource,TKey>(IEnumerable<TSource>, IEnumerable<TKey>, Func<TSource,TKey>, IEqualityComparer<TKey>)	Produces the set difference of two sequences according to a specified key selector function.
ExceptBy<TSource,TKey>(IEnumerable<TSource>, IEnumerable<TKey>, Func<TSource,TKey>)	Produces the set difference of two sequences according to a specified key selector function.
First<TSource>(IEnumerable<TSource>, Func<TSource,Boolean>)	Returns the first element in a sequence that satisfies a specified condition.
First<TSource>(IEnumerable<TSource>)	Returns the first element of a sequence.
FirstOrDefault<TSource>(IEnumerable<TSource>, TSource)	Returns the first element of a sequence, or a specified default value if the sequence contains no elements.
FirstOrDefault<TSource>(IEnumerable<TSource>, Func<TSource,Boolean>, TSource)	Returns the first element of the sequence that satisfies a condition, or a specified default value if no such element is found.
FirstOrDefault<TSource>(IEnumerable<TSource>, Func<TSource,Boolean>)	Returns the first element of the sequence that satisfies a condition or a default value if no such element is found.
FirstOrDefault<TSource>(IEnumerable<TSource>)	Returns the first element of a sequence, or a default value if the sequence contains no elements.
GroupBy<TSource,TKey>(IEnumerable<TSource>, Func<TSource,TKey>, IEqualityComparer<TKey>)	Groups the elements of a sequence according to a specified key selector function and compares the keys by using a specified comparer.
GroupBy<TSource,TKey>(IEnumerable<TSource>, Func<TSource,TKey>)	Groups the elements of a sequence according to a specified key selector function.
GroupBy<TSource,TKey,TElement>(IEnumerable<TSource>, Func<TSource,TKey>, Func<TSource,TElement>, IEqualityComparer<TKey>)	Groups the elements of a sequence according to a key selector function. The keys are compared by using a comparer and each group's elements are projected by using a specified function.
GroupBy<TSource,TKey,TElement>(IEnumerable<TSource>, Func<TSource,TKey>, Func<TSource,TElement>)	Groups the elements of a sequence according to a specified key selector function and projects the elements for each group by using a specified function.
GroupBy<TSource,TKey,TResult>(IEnumerable<TSource>, Func<TSource,TKey>, Func<TKey,IEnumerable<TSource>,TResult>, IEqualityComparer<TKey>)	Groups the elements of a sequence according to a specified key selector function and creates a result value from each group and its key. The keys are compared by using a specified comparer.
GroupBy<TSource,TKey,TResult>(IEnumerable<TSource>, Func<TSource,TKey>, Func<TKey,IEnumerable<TSource>,TResult>)	Groups the elements of a sequence according to a specified key selector function and creates a result value from each group and its key.
GroupBy<TSource,TKey,TElement,TResult>(IEnumerable<TSource>, Func<TSource, TKey>, Func<TSource,TElement>, Func<TKey,IEnumerable<TElement>, TResult>, IEqualityComparer<TKey>)	Groups the elements of a sequence according to a specified key selector function and creates a result value from each group and its key. Key values are compared by using a specified comparer, and the elements of each group are projected by using a specified function.
GroupBy<TSource,TKey,TElement,TResult>(IEnumerable<TSource>, Func<TSource,TKey>, Func<TSource,TElement>, Func<TKey,IEnumerable<TElement>,TResult>)	Groups the elements of a sequence according to a specified key selector function and creates a result value from each group and its key. The elements of each group are projected by using a specified function.
GroupJoin<TOuter,TInner,TKey,TResult>(IEnumerable<TOuter>, IEnumerable<TInner>, Func<TOuter,TKey>, Func<TInner,TKey>, Func<TOuter,IEnumerable<TInner>, TResult>, IEqualityComparer<TKey>)	Correlates the elements of two sequences based on key equality and groups the results. A specified IEqualityComparer<T> is used to compare keys.
GroupJoin<TOuter,TInner,TKey,TResult>(IEnumerable<TOuter>, IEnumerable<TInner>, Func<TOuter,TKey>, Func<TInner,TKey>, Func<TOuter,IEnumerable<TInner>, TResult>)	Correlates the elements of two sequences based on equality of keys and groups the results. The default equality comparer is used to compare keys.
Index<TSource>(IEnumerable<TSource>)	Returns an enumerable that incorporates the element's index into a tuple.
Intersect<TSource>(IEnumerable<TSource>, IEnumerable<TSource>, IEqualityComparer<TSource>)	Produces the set intersection of two sequences by using the specified IEqualityComparer<T> to compare values.
Intersect<TSource>(IEnumerable<TSource>, IEnumerable<TSource>)	Produces the set intersection of two sequences by using the default equality comparer to compare values.
IntersectBy<TSource,TKey>(IEnumerable<TSource>, IEnumerable<TKey>, Func<TSource,TKey>, IEqualityComparer<TKey>)	Produces the set intersection of two sequences according to a specified key selector function.
IntersectBy<TSource,TKey>(IEnumerable<TSource>, IEnumerable<TKey>, Func<TSource,TKey>)	Produces the set intersection of two sequences according to a specified key selector function.
Join<TOuter,TInner,TKey,TResult>(IEnumerable<TOuter>, IEnumerable<TInner>, Func<TOuter,TKey>, Func<TInner,TKey>, Func<TOuter,TInner,TResult>, IEqualityComparer<TKey>)	Correlates the elements of two sequences based on matching keys. A specified IEqualityComparer<T> is used to compare keys.
Join<TOuter,TInner,TKey,TResult>(IEnumerable<TOuter>, IEnumerable<TInner>, Func<TOuter,TKey>, Func<TInner,TKey>, Func<TOuter,TInner,TResult>)	Correlates the elements of two sequences based on matching keys. The default equality comparer is used to compare keys.
Last<TSource>(IEnumerable<TSource>, Func<TSource,Boolean>)	Returns the last element of a sequence that satisfies a specified condition.
Last<TSource>(IEnumerable<TSource>)	Returns the last element of a sequence.
LastOrDefault<TSource>(IEnumerable<TSource>, TSource)	Returns the last element of a sequence, or a specified default value if the sequence contains no elements.
LastOrDefault<TSource>(IEnumerable<TSource>, Func<TSource,Boolean>, TSource)	Returns the last element of a sequence that satisfies a condition, or a specified default value if no such element is found.
LastOrDefault<TSource>(IEnumerable<TSource>, Func<TSource,Boolean>)	Returns the last element of a sequence that satisfies a condition or a default value if no such element is found.
LastOrDefault<TSource>(IEnumerable<TSource>)	Returns the last element of a sequence, or a default value if the sequence contains no elements.
LongCount<TSource>(IEnumerable<TSource>, Func<TSource,Boolean>)	Returns an Int64 that represents how many elements in a sequence satisfy a condition.
LongCount<TSource>(IEnumerable<TSource>)	Returns an Int64 that represents the total number of elements in a sequence.
Max<TSource>(IEnumerable<TSource>, IComparer<TSource>)	Returns the maximum value in a generic sequence.
Max<TSource>(IEnumerable<TSource>, Func<TSource,Decimal>)	Invokes a transform function on each element of a sequence and returns the maximum Decimal value.
Max<TSource>(IEnumerable<TSource>, Func<TSource,Double>)	Invokes a transform function on each element of a sequence and returns the maximum Double value.
Max<TSource>(IEnumerable<TSource>, Func<TSource,Int32>)	Invokes a transform function on each element of a sequence and returns the maximum Int32 value.
Max<TSource>(IEnumerable<TSource>, Func<TSource,Int64>)	Invokes a transform function on each element of a sequence and returns the maximum Int64 value.
Max<TSource>(IEnumerable<TSource>, Func<TSource,Nullable<Decimal>>)	Invokes a transform function on each element of a sequence and returns the maximum nullable Decimal value.
Max<TSource>(IEnumerable<TSource>, Func<TSource,Nullable<Double>>)	Invokes a transform function on each element of a sequence and returns the maximum nullable Double value.
Max<TSource>(IEnumerable<TSource>, Func<TSource,Nullable<Int32>>)	Invokes a transform function on each element of a sequence and returns the maximum nullable Int32 value.
Max<TSource>(IEnumerable<TSource>, Func<TSource,Nullable<Int64>>)	Invokes a transform function on each element of a sequence and returns the maximum nullable Int64 value.
Max<TSource>(IEnumerable<TSource>, Func<TSource,Nullable<Single>>)	Invokes a transform function on each element of a sequence and returns the maximum nullable Single value.
Max<TSource>(IEnumerable<TSource>, Func<TSource,Single>)	Invokes a transform function on each element of a sequence and returns the maximum Single value.
Max<TSource>(IEnumerable<TSource>)	Returns the maximum value in a generic sequence.
Max<TSource,TResult>(IEnumerable<TSource>, Func<TSource,TResult>)	Invokes a transform function on each element of a generic sequence and returns the maximum resulting value.
MaxBy<TSource,TKey>(IEnumerable<TSource>, Func<TSource,TKey>, IComparer<TKey>)	Returns the maximum value in a generic sequence according to a specified key selector function and key comparer.
MaxBy<TSource,TKey>(IEnumerable<TSource>, Func<TSource,TKey>)	Returns the maximum value in a generic sequence according to a specified key selector function.
Min<TSource>(IEnumerable<TSource>, IComparer<TSource>)	Returns the minimum value in a generic sequence.
Min<TSource>(IEnumerable<TSource>, Func<TSource,Decimal>)	Invokes a transform function on each element of a sequence and returns the minimum Decimal value.
Min<TSource>(IEnumerable<TSource>, Func<TSource,Double>)	Invokes a transform function on each element of a sequence and returns the minimum Double value.
Min<TSource>(IEnumerable<TSource>, Func<TSource,Int32>)	Invokes a transform function on each element of a sequence and returns the minimum Int32 value.
Min<TSource>(IEnumerable<TSource>, Func<TSource,Int64>)	Invokes a transform function on each element of a sequence and returns the minimum Int64 value.
Min<TSource>(IEnumerable<TSource>, Func<TSource,Nullable<Decimal>>)	Invokes a transform function on each element of a sequence and returns the minimum nullable Decimal value.
Min<TSource>(IEnumerable<TSource>, Func<TSource,Nullable<Double>>)	Invokes a transform function on each element of a sequence and returns the minimum nullable Double value.
Min<TSource>(IEnumerable<TSource>, Func<TSource,Nullable<Int32>>)	Invokes a transform function on each element of a sequence and returns the minimum nullable Int32 value.
Min<TSource>(IEnumerable<TSource>, Func<TSource,Nullable<Int64>>)	Invokes a transform function on each element of a sequence and returns the minimum nullable Int64 value.
Min<TSource>(IEnumerable<TSource>, Func<TSource,Nullable<Single>>)	Invokes a transform function on each element of a sequence and returns the minimum nullable Single value.
Min<TSource>(IEnumerable<TSource>, Func<TSource,Single>)	Invokes a transform function on each element of a sequence and returns the minimum Single value.
Min<TSource>(IEnumerable<TSource>)	Returns the minimum value in a generic sequence.
Min<TSource,TResult>(IEnumerable<TSource>, Func<TSource,TResult>)	Invokes a transform function on each element of a generic sequence and returns the minimum resulting value.
MinBy<TSource,TKey>(IEnumerable<TSource>, Func<TSource,TKey>, IComparer<TKey>)	Returns the minimum value in a generic sequence according to a specified key selector function and key comparer.
MinBy<TSource,TKey>(IEnumerable<TSource>, Func<TSource,TKey>)	Returns the minimum value in a generic sequence according to a specified key selector function.
OfType<TResult>(IEnumerable)	Filters the elements of an IEnumerable based on a specified type.
Order<T>(IEnumerable<T>, IComparer<T>)	Sorts the elements of a sequence in ascending order.
Order<T>(IEnumerable<T>)	Sorts the elements of a sequence in ascending order.
OrderBy<TSource,TKey>(IEnumerable<TSource>, Func<TSource,TKey>, IComparer<TKey>)	Sorts the elements of a sequence in ascending order by using a specified comparer.
OrderBy<TSource,TKey>(IEnumerable<TSource>, Func<TSource,TKey>)	Sorts the elements of a sequence in ascending order according to a key.
OrderByDescending<TSource,TKey>(IEnumerable<TSource>, Func<TSource,TKey>, IComparer<TKey>)	Sorts the elements of a sequence in descending order by using a specified comparer.
OrderByDescending<TSource,TKey>(IEnumerable<TSource>, Func<TSource,TKey>)	Sorts the elements of a sequence in descending order according to a key.
OrderDescending<T>(IEnumerable<T>, IComparer<T>)	Sorts the elements of a sequence in descending order.
OrderDescending<T>(IEnumerable<T>)	Sorts the elements of a sequence in descending order.
Prepend<TSource>(IEnumerable<TSource>, TSource)	Adds a value to the beginning of the sequence.
Reverse<TSource>(IEnumerable<TSource>)	Inverts the order of the elements in a sequence.
Select<TSource,TResult>(IEnumerable<TSource>, Func<TSource,TResult>)	Projects each element of a sequence into a new form.
Select<TSource,TResult>(IEnumerable<TSource>, Func<TSource,Int32,TResult>)	Projects each element of a sequence into a new form by incorporating the element's index.
SelectMany<TSource,TResult>(IEnumerable<TSource>, Func<TSource,IEnumerable<TResult>>)	Projects each element of a sequence to an IEnumerable<T> and flattens the resulting sequences into one sequence.
SelectMany<TSource,TResult>(IEnumerable<TSource>, Func<TSource,Int32,IEnumerable<TResult>>)	Projects each element of a sequence to an IEnumerable<T>, and flattens the resulting sequences into one sequence. The index of each source element is used in the projected form of that element.
SelectMany<TSource,TCollection,TResult>(IEnumerable<TSource>, Func<TSource,IEnumerable<TCollection>>, Func<TSource,TCollection,TResult>)	Projects each element of a sequence to an IEnumerable<T>, flattens the resulting sequences into one sequence, and invokes a result selector function on each element therein.
SelectMany<TSource,TCollection,TResult>(IEnumerable<TSource>, Func<TSource,Int32,IEnumerable<TCollection>>, Func<TSource,TCollection,TResult>)	Projects each element of a sequence to an IEnumerable<T>, flattens the resulting sequences into one sequence, and invokes a result selector function on each element therein. The index of each source element is used in the intermediate projected form of that element.
SequenceEqual<TSource>(IEnumerable<TSource>, IEnumerable<TSource>, IEqualityComparer<TSource>)	Determines whether two sequences are equal by comparing their elements by using a specified IEqualityComparer<T>.
SequenceEqual<TSource>(IEnumerable<TSource>, IEnumerable<TSource>)	Determines whether two sequences are equal by comparing the elements by using the default equality comparer for their type.
Single<TSource>(IEnumerable<TSource>, Func<TSource,Boolean>)	Returns the only element of a sequence that satisfies a specified condition, and throws an exception if more than one such element exists.
Single<TSource>(IEnumerable<TSource>)	Returns the only element of a sequence, and throws an exception if there is not exactly one element in the sequence.
SingleOrDefault<TSource>(IEnumerable<TSource>, TSource)	Returns the only element of a sequence, or a specified default value if the sequence is empty; this method throws an exception if there is more than one element in the sequence.
SingleOrDefault<TSource>(IEnumerable<TSource>, Func<TSource,Boolean>, TSource)	Returns the only element of a sequence that satisfies a specified condition, or a specified default value if no such element exists; this method throws an exception if more than one element satisfies the condition.
SingleOrDefault<TSource>(IEnumerable<TSource>, Func<TSource,Boolean>)	Returns the only element of a sequence that satisfies a specified condition or a default value if no such element exists; this method throws an exception if more than one element satisfies the condition.
SingleOrDefault<TSource>(IEnumerable<TSource>)	Returns the only element of a sequence, or a default value if the sequence is empty; this method throws an exception if there is more than one element in the sequence.
Skip<TSource>(IEnumerable<TSource>, Int32)	Bypasses a specified number of elements in a sequence and then returns the remaining elements.
SkipLast<TSource>(IEnumerable<TSource>, Int32)	Returns a new enumerable collection that contains the elements from `source` with the last `count` elements of the source collection omitted.
SkipWhile<TSource>(IEnumerable<TSource>, Func<TSource,Boolean>)	Bypasses elements in a sequence as long as a specified condition is true and then returns the remaining elements.
SkipWhile<TSource>(IEnumerable<TSource>, Func<TSource,Int32,Boolean>)	Bypasses elements in a sequence as long as a specified condition is true and then returns the remaining elements. The element's index is used in the logic of the predicate function.
Sum<TSource>(IEnumerable<TSource>, Func<TSource,Decimal>)	Computes the sum of the sequence of Decimal values that are obtained by invoking a transform function on each element of the input sequence.
Sum<TSource>(IEnumerable<TSource>, Func<TSource,Double>)	Computes the sum of the sequence of Double values that are obtained by invoking a transform function on each element of the input sequence.
Sum<TSource>(IEnumerable<TSource>, Func<TSource,Int32>)	Computes the sum of the sequence of Int32 values that are obtained by invoking a transform function on each element of the input sequence.
Sum<TSource>(IEnumerable<TSource>, Func<TSource,Int64>)	Computes the sum of the sequence of Int64 values that are obtained by invoking a transform function on each element of the input sequence.
Sum<TSource>(IEnumerable<TSource>, Func<TSource,Nullable<Decimal>>)	Computes the sum of the sequence of nullable Decimal values that are obtained by invoking a transform function on each element of the input sequence.
Sum<TSource>(IEnumerable<TSource>, Func<TSource,Nullable<Double>>)	Computes the sum of the sequence of nullable Double values that are obtained by invoking a transform function on each element of the input sequence.
Sum<TSource>(IEnumerable<TSource>, Func<TSource,Nullable<Int32>>)	Computes the sum of the sequence of nullable Int32 values that are obtained by invoking a transform function on each element of the input sequence.
Sum<TSource>(IEnumerable<TSource>, Func<TSource,Nullable<Int64>>)	Computes the sum of the sequence of nullable Int64 values that are obtained by invoking a transform function on each element of the input sequence.
Sum<TSource>(IEnumerable<TSource>, Func<TSource,Nullable<Single>>)	Computes the sum of the sequence of nullable Single values that are obtained by invoking a transform function on each element of the input sequence.
Sum<TSource>(IEnumerable<TSource>, Func<TSource,Single>)	Computes the sum of the sequence of Single values that are obtained by invoking a transform function on each element of the input sequence.
Take<TSource>(IEnumerable<TSource>, Int32)	Returns a specified number of contiguous elements from the start of a sequence.
Take<TSource>(IEnumerable<TSource>, Range)	Returns a specified range of contiguous elements from a sequence.
TakeLast<TSource>(IEnumerable<TSource>, Int32)	Returns a new enumerable collection that contains the last `count` elements from `source`.
TakeWhile<TSource>(IEnumerable<TSource>, Func<TSource,Boolean>)	Returns elements from a sequence as long as a specified condition is true.
TakeWhile<TSource>(IEnumerable<TSource>, Func<TSource,Int32,Boolean>)	Returns elements from a sequence as long as a specified condition is true. The element's index is used in the logic of the predicate function.
ToArray<TSource>(IEnumerable<TSource>)	Creates an array from a IEnumerable<T>.
ToDictionary<TSource,TKey>(IEnumerable<TSource>, Func<TSource,TKey>, IEqualityComparer<TKey>)	Creates a Dictionary<TKey,TValue> from an IEnumerable<T> according to a specified key selector function and key comparer.
ToDictionary<TSource,TKey>(IEnumerable<TSource>, Func<TSource,TKey>)	Creates a Dictionary<TKey,TValue> from an IEnumerable<T> according to a specified key selector function.
ToDictionary<TSource,TKey,TElement>(IEnumerable<TSource>, Func<TSource,TKey>, Func<TSource,TElement>, IEqualityComparer<TKey>)	Creates a Dictionary<TKey,TValue> from an IEnumerable<T> according to a specified key selector function, a comparer, and an element selector function.
ToDictionary<TSource,TKey,TElement>(IEnumerable<TSource>, Func<TSource,TKey>, Func<TSource,TElement>)	Creates a Dictionary<TKey,TValue> from an IEnumerable<T> according to specified key selector and element selector functions.
ToHashSet<TSource>(IEnumerable<TSource>, IEqualityComparer<TSource>)	Creates a HashSet<T> from an IEnumerable<T> using the `comparer` to compare keys.
ToHashSet<TSource>(IEnumerable<TSource>)	Creates a HashSet<T> from an IEnumerable<T>.
ToList<TSource>(IEnumerable<TSource>)	Creates a List<T> from an IEnumerable<T>.
ToLookup<TSource,TKey>(IEnumerable<TSource>, Func<TSource,TKey>, IEqualityComparer<TKey>)	Creates a Lookup<TKey,TElement> from an IEnumerable<T> according to a specified key selector function and key comparer.
ToLookup<TSource,TKey>(IEnumerable<TSource>, Func<TSource,TKey>)	Creates a Lookup<TKey,TElement> from an IEnumerable<T> according to a specified key selector function.
ToLookup<TSource,TKey,TElement>(IEnumerable<TSource>, Func<TSource,TKey>, Func<TSource,TElement>, IEqualityComparer<TKey>)	Creates a Lookup<TKey,TElement> from an IEnumerable<T> according to a specified key selector function, a comparer and an element selector function.
ToLookup<TSource,TKey,TElement>(IEnumerable<TSource>, Func<TSource,TKey>, Func<TSource,TElement>)	Creates a Lookup<TKey,TElement> from an IEnumerable<T> according to specified key selector and element selector functions.
TryGetNonEnumeratedCount<TSource>(IEnumerable<TSource>, Int32)	Attempts to determine the number of elements in a sequence without forcing an enumeration.
Union<TSource>(IEnumerable<TSource>, IEnumerable<TSource>, IEqualityComparer<TSource>)	Produces the set union of two sequences by using a specified IEqualityComparer<T>.
Union<TSource>(IEnumerable<TSource>, IEnumerable<TSource>)	Produces the set union of two sequences by using the default equality comparer.
UnionBy<TSource,TKey>(IEnumerable<TSource>, IEnumerable<TSource>, Func<TSource,TKey>, IEqualityComparer<TKey>)	Produces the set union of two sequences according to a specified key selector function.
UnionBy<TSource,TKey>(IEnumerable<TSource>, IEnumerable<TSource>, Func<TSource,TKey>)	Produces the set union of two sequences according to a specified key selector function.
Where<TSource>(IEnumerable<TSource>, Func<TSource,Boolean>)	Filters a sequence of values based on a predicate.
Where<TSource>(IEnumerable<TSource>, Func<TSource,Int32,Boolean>)	Filters a sequence of values based on a predicate. Each element's index is used in the logic of the predicate function.
Zip<TFirst,TSecond>(IEnumerable<TFirst>, IEnumerable<TSecond>)	Produces a sequence of tuples with elements from the two specified sequences.
Zip<TFirst,TSecond,TThird>(IEnumerable<TFirst>, IEnumerable<TSecond>, IEnumerable<TThird>)	Produces a sequence of tuples with elements from the three specified sequences.
Zip<TFirst,TSecond,TResult>(IEnumerable<TFirst>, IEnumerable<TSecond>, Func<TFirst,TSecond,TResult>)	Applies a specified function to the corresponding elements of two sequences, producing a sequence of the results.
AsParallel(IEnumerable)	Enables parallelization of a query.
AsParallel<TSource>(IEnumerable<TSource>)	Enables parallelization of a query.
AsQueryable(IEnumerable)	Converts an IEnumerable to an IQueryable.
AsQueryable<TElement>(IEnumerable<TElement>)	Converts a generic IEnumerable<T> to a generic IQueryable<T>.
AsMemory<T>(ArraySegment<T>, Int32, Int32)	Creates a new memory region over the portion of the target array segment beginning at a specified position with a specified length.
AsMemory<T>(ArraySegment<T>, Int32)	Creates a new memory region over the portion of the target array segment starting at a specified position to the end of the segment.
AsMemory<T>(ArraySegment<T>)	Creates a new memory region over the portion of the target array segment.
AsSpan<T>(ArraySegment<T>, Index)	Creates a new span over a portion of the target array segment beginning at a specified index and ending at the end of the segment.
AsSpan<T>(ArraySegment<T>, Int32, Int32)	Creates a new span over a portion of a target array segment from a specified position for a specified length.
AsSpan<T>(ArraySegment<T>, Int32)	Creates a new span over a portion of a target array segment from a specified position to the end of the segment.
AsSpan<T>(ArraySegment<T>, Range)	Creates a new span over a portion of a target array segment using the range start and end indexes.
AsSpan<T>(ArraySegment<T>)	Creates a new span over a target array segment.
Ancestors<T>(IEnumerable<T>, XName)	Returns a filtered collection of elements that contains the ancestors of every node in the source collection. Only elements that have a matching XName are included in the collection.
Ancestors<T>(IEnumerable<T>)	Returns a collection of elements that contains the ancestors of every node in the source collection.
DescendantNodes<T>(IEnumerable<T>)	Returns a collection of the descendant nodes of every document and element in the source collection.
Descendants<T>(IEnumerable<T>, XName)	Returns a filtered collection of elements that contains the descendant elements of every element and document in the source collection. Only elements that have a matching XName are included in the collection.
Descendants<T>(IEnumerable<T>)	Returns a collection of elements that contains the descendant elements of every element and document in the source collection.
Elements<T>(IEnumerable<T>, XName)	Returns a filtered collection of the child elements of every element and document in the source collection. Only elements that have a matching XName are included in the collection.
Elements<T>(IEnumerable<T>)	Returns a collection of the child elements of every element and document in the source collection.
InDocumentOrder<T>(IEnumerable<T>)	Returns a collection of nodes that contains all nodes in the source collection, sorted in document order.
Nodes<T>(IEnumerable<T>)	Returns a collection of the child nodes of every document and element in the source collection.
Remove<T>(IEnumerable<T>)	Removes every node in the source collection from its parent node.

Applies to

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