ICollection<T> Interface

Reference

Definition

Namespace:: System.Collections.Generic

Assembly:: System.Runtime.dll

Assembly:: mscorlib.dll

Assembly:: netstandard.dll

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.

Defines methods to manipulate generic collections.

generic <typename T>
public interface class ICollection : System::Collections::Generic::IEnumerable<T>

public interface ICollection<T> : System.Collections.Generic.IEnumerable<T>

type ICollection<'T> = interface
    interface seq<'T>
    interface IEnumerable

Public Interface ICollection(Of T)
Implements IEnumerable(Of T)

Type Parameters

T

The type of the elements in the collection.

Derived: Microsoft.Extensions.AI.AdditionalPropertiesDictionary

Microsoft.Extensions.AI.GeneratedEmbeddings<TEmbedding>

Microsoft.Extensions.DependencyInjection.IServiceCollection

Microsoft.Extensions.DependencyInjection.ServiceCollection

Microsoft.Extensions.Primitives.StringValues

More…

Implements: IEnumerable<T> IEnumerable

Examples

The following example implements the ICollection<T> interface to create a collection of custom Box objects named BoxCollection. Each Box has height, length, and width properties, which are used to define equality. Equality can be defined as all dimensions being the same or the volume being the same. The Box class implements the IEquatable<T> interface to define the default equality as the dimensions being the same.

The BoxCollection class implements the Contains method to use the default equality to determine whether a Box is in the collection. This method is used by the Add method so that each Box added to the collection has a unique set of dimensions. The BoxCollection class also provides an overload of the Contains method that takes a specified EqualityComparer<T> object, such as BoxSameDimensions and BoxSameVol classes in the example.

This example also implements an IEnumerator<T> interface for the BoxCollection class so that the collection can be enumerated.

using System;
using System.Collections;
using System.Collections.Generic;

class Program
{

    static void Main(string[] args)
    {

        BoxCollection bxList = new BoxCollection();

        bxList.Add(new Box(10, 4, 6));
        bxList.Add(new Box(4, 6, 10));
        bxList.Add(new Box(6, 10, 4));
        bxList.Add(new Box(12, 8, 10));

        // Same dimensions. Cannot be added:
        bxList.Add(new Box(10, 4, 6));

        // Test the Remove method.
        Display(bxList);
        Console.WriteLine("Removing 6x10x4");
        bxList.Remove(new Box(6, 10, 4));
        Display(bxList);

        // Test the Contains method.
        Box BoxCheck = new Box(8, 12, 10);
        Console.WriteLine("Contains {0}x{1}x{2} by dimensions: {3}",
            BoxCheck.Height.ToString(), BoxCheck.Length.ToString(),
            BoxCheck.Width.ToString(), bxList.Contains(BoxCheck).ToString());

        // Test the Contains method overload with a specified equality comparer.
        Console.WriteLine("Contains {0}x{1}x{2} by volume: {3}",
            BoxCheck.Height.ToString(), BoxCheck.Length.ToString(),
            BoxCheck.Width.ToString(), bxList.Contains(BoxCheck,
            new BoxSameVol()).ToString());
    }
    public static void Display(BoxCollection bxList)
    {
        Console.WriteLine("\nHeight\tLength\tWidth\tHash Code");
        foreach (Box bx in bxList)
        {
            Console.WriteLine("{0}\t{1}\t{2}\t{3}",
                bx.Height.ToString(), bx.Length.ToString(),
                bx.Width.ToString(), bx.GetHashCode().ToString());
        }

        // Results by manipulating the enumerator directly:

        //IEnumerator enumerator = bxList.GetEnumerator();
        //Console.WriteLine("\nHeight\tLength\tWidth\tHash Code");
        //while (enumerator.MoveNext())
        //{
        //    Box b = (Box)enumerator.Current;
        //    Console.WriteLine("{0}\t{1}\t{2}\t{3}",
        //    b.Height.ToString(), b.Length.ToString(),
        //    b.Width.ToString(), b.GetHashCode().ToString());
        //}

        Console.WriteLine();
    }

}

public class Box : IEquatable<Box>
{

    public Box(int h, int l, int w)
    {
        this.Height = h;
        this.Length = l;
        this.Width = w;
    }
    public int Height { get; set; }
    public int Length { get; set; }
    public int Width { get; set; }

    // Defines equality using the
    // BoxSameDimensions equality comparer.
    public bool Equals(Box other)
    {
        if (new BoxSameDimensions().Equals(this, other))
        {
            return true;
        }
        else
        {
            return false;
        }
    }

    public override bool Equals(object obj)
    {
        return base.Equals(obj);
    }

    public override int GetHashCode()
    {
        return base.GetHashCode();
    }
}

public class BoxCollection : ICollection<Box>
{
    // The generic enumerator obtained from IEnumerator<Box>
    // by GetEnumerator can also be used with the non-generic IEnumerator.
    // To avoid a naming conflict, the non-generic IEnumerable method
    // is explicitly implemented.

    public IEnumerator<Box> GetEnumerator()
    {
        return new BoxEnumerator(this);
    }
    IEnumerator IEnumerable.GetEnumerator()
    {
        return new BoxEnumerator(this);
    }

    // The inner collection to store objects.
    private List<Box> innerCol;

    public BoxCollection()
    {
        innerCol = new List<Box>();
    }

    // Adds an index to the collection.
    public Box this[int index]
    {
        get { return (Box)innerCol[index]; }
        set { innerCol[index] = value; }
    }

    // Determines if an item is in the collection
    // by using the BoxSameDimensions equality comparer.
    public bool Contains(Box item)
    {
        bool found = false;

        foreach (Box bx in innerCol)
        {
            // Equality defined by the Box
            // class's implmentation of IEquatable<T>.
            if (bx.Equals(item))
            {
                found = true;
            }
        }

        return found;
    }

    // Determines if an item is in the
    // collection by using a specified equality comparer.
    public bool Contains(Box item, EqualityComparer<Box> comp)
    {
        bool found = false;

        foreach (Box bx in innerCol)
        {
            if (comp.Equals(bx, item))
            {
                found = true;
            }
        }

        return found;
    }

    // Adds an item if it is not already in the collection
    // as determined by calling the Contains method.
    public void Add(Box item)
    {

        if (!Contains(item))
        {
            innerCol.Add(item);
        }
        else
        {
            Console.WriteLine("A box with {0}x{1}x{2} dimensions was already added to the collection.",
                item.Height.ToString(), item.Length.ToString(), item.Width.ToString());
        }
    }

    public void Clear()
    {
        innerCol.Clear();
    }

    public void CopyTo(Box[] array, int arrayIndex)
    {
        if (array == null)
           throw new ArgumentNullException("The array cannot be null.");
        if (arrayIndex < 0)
           throw new ArgumentOutOfRangeException("The starting array index cannot be negative.");
        if (Count > array.Length - arrayIndex)
           throw new ArgumentException("The destination array has fewer elements than the collection.");

        for (int i = 0; i < innerCol.Count; i++) {
            array[i + arrayIndex] = innerCol[i];
        }
    }

    public int Count
    {
        get
        {
            return innerCol.Count;
        }
    }

    public bool IsReadOnly
    {
        get { return false; }
    }

    public bool Remove(Box item)
    {
        bool result = false;

        // Iterate the inner collection to
        // find the box to be removed.
        for (int i = 0; i < innerCol.Count; i++)
        {

            Box curBox = (Box)innerCol[i];

            if (new BoxSameDimensions().Equals(curBox, item))
            {
                innerCol.RemoveAt(i);
                result = true;
                break;
            }
        }
        return result;
    }
}


// Defines the enumerator for the Boxes collection.
// (Some prefer this class nested in the collection class.)
public class BoxEnumerator : IEnumerator<Box>
{
    private BoxCollection _collection;
    private int curIndex;
    private Box curBox;

    public BoxEnumerator(BoxCollection collection)
    {
        _collection = collection;
        curIndex = -1;
        curBox = default(Box);
    }

    public bool MoveNext()
    {
        //Avoids going beyond the end of the collection.
        if (++curIndex >= _collection.Count)
        {
            return false;
        }
        else
        {
            // Set current box to next item in collection.
            curBox = _collection[curIndex];
        }
        return true;
    }

    public void Reset() { curIndex = -1; }

    void IDisposable.Dispose() { }

    public Box Current
    {
        get { return curBox; }
    }

    object IEnumerator.Current
    {
        get { return Current; }
    }
}

// Defines two boxes as equal if they have the same dimensions.
public class BoxSameDimensions : EqualityComparer<Box>
{

    public override bool Equals(Box b1, Box b2)
    {
        if (b1.Height == b2.Height && b1.Length == b2.Length
                            && b1.Width == b2.Width)
        {
            return true;
        }
        else
        {
            return false;
        }
    }

    public override int GetHashCode(Box bx)
    {
        int hCode = bx.Height ^ bx.Length ^ bx.Width;
        return hCode.GetHashCode();
    }
}

// Defines two boxes as equal if they have the same volume.
public class BoxSameVol : EqualityComparer<Box>
{

    public override bool Equals(Box b1, Box b2)
    {
        if ((b1.Height * b1.Length * b1.Width) ==
                (b2.Height * b2.Length * b2.Width))
        {
            return true;
        }
        else
        {
            return false;
        }
    }

    public override int GetHashCode(Box bx)
    {
        int hCode = bx.Height ^ bx.Length ^ bx.Width;
        Console.WriteLine("HC: {0}", hCode.GetHashCode());
        return hCode.GetHashCode();
    }
}


/*
This code example displays the following output:
================================================

A box with 10x4x6 dimensions was already added to the collection.

Height  Length  Width   Hash Code
10      4       6       46104728
4       6       10      12289376
6       10      4       43495525
12      8       10      55915408

Removing 6x10x4

Height  Length  Width   Hash Code
10      4       6       46104728
4       6       10      12289376
12      8       10      55915408

Contains 8x12x10 by dimensions: False
Contains 8x12x10 by volume: True
 */

Imports System.Collections
Imports System.Collections.Generic

Class Program
    Public Shared Sub Main(ByVal args() As String)

        Dim bxList As BoxCollection = New BoxCollection()

        bxList.Add(New Box(10, 4, 6))
        bxList.Add(New Box(4, 6, 10))
        bxList.Add(New Box(6, 10, 4))
        bxList.Add(New Box(12, 8, 10))

        ' Same dimensions. Cannot be added:
        bxList.Add(New Box(10, 4, 6))

        ' Test the Remove method.
        Display(bxList)
        Console.WriteLine("Removing 6x10x4")
        bxList.Remove(New Box(6, 10, 4))
        Display(bxList)

        ' Test the Contains method
        Dim BoxCheck As Box = New Box(8, 12, 10)
        Console.WriteLine("Contains {0}x{1}x{2} by dimensions: {3}", BoxCheck.Height.ToString(),
            BoxCheck.Length.ToString(), BoxCheck.Width.ToString(), bxList.Contains(BoxCheck).ToString())

        ' Test the Contains method overload with a specified equality comparer.
        Console.WriteLine("Contains {0}x{1}x{2} by volume: {3}", BoxCheck.Height.ToString(),
            BoxCheck.Length.ToString(), BoxCheck.Width.ToString(),
            bxList.Contains(BoxCheck, New BoxSameVol()).ToString())

    End Sub

    Public Shared Sub Display(ByVal bxList As BoxCollection)
        Console.WriteLine(vbLf & "Height" & vbTab & "Length" & vbTab & "Width" & vbTab & "Hash Code")
        For Each bx As Box In bxList
            Console.WriteLine("{0}" & vbTab & "{1}" & vbTab & "{2}" & vbTab & "{3}", bx.Height.ToString(), bx.Length.ToString(), bx.Width.ToString(), bx.GetHashCode().ToString())
        Next
        Console.WriteLine()
    End Sub
End Class

Public Class Box : Implements IEquatable(Of Box)
    Public Sub New(ByVal h As Integer, ByVal l As Integer, ByVal w As Integer)
        Me.Height = h
        Me.Length = l
        Me.Width = w
    End Sub

    Private _Height As Integer
    Public Property Height() As Integer
        Get
            Return _Height
        End Get
        Set(ByVal value As Integer)
            _Height = value
        End Set
    End Property

    Private _Length As Integer
    Public Property Length() As Integer
        Get
            Return _Length
        End Get
        Set(ByVal value As Integer)
            _Length = value
        End Set
    End Property

    Private _Width As Integer
    Public Property Width() As Integer
        Get
            Return _Width
        End Get
        Set(ByVal value As Integer)
            _Width = value
        End Set
    End Property

    Public Overloads Function Equals(ByVal other As Box) As Boolean Implements IEquatable(Of Box).Equals
        Dim BoxSameDim = New BoxSameDimensions()
        If BoxSameDim.Equals(Me, other) Then
            Return True
        Else
            Return False
        End If
    End Function

    Public Overrides Function Equals(ByVal obj As Object) As Boolean
        Return MyBase.Equals(obj)
    End Function

    Public Overrides Function GetHashCode() As Integer
        Return MyBase.GetHashCode()
    End Function
End Class

Public Class BoxCollection : Implements ICollection(Of Box)
    ' The generic enumerator obtained from IEnumerator<Box> by GetEnumerator can also
    ' be used with the non-generic IEnumerator. To avoid a naming conflict, 
    ' the non-generic IEnumerable method is explicitly implemented.

    Public Function GetEnumerator() As IEnumerator(Of Box) _
        Implements IEnumerable(Of Box).GetEnumerator

        Return New BoxEnumerator(Me)
    End Function

    Private Function GetEnumerator1() As IEnumerator _
        Implements IEnumerable.GetEnumerator

        Return Me.GetEnumerator()
    End Function

    ' The inner collection to store objects.
    Private innerCol As List(Of Box)

    Public Sub New()
        innerCol = New List(Of Box)
    End Sub

    ' Adds an index to the collection.
    Default Public Property Item(ByVal index As Integer) As Box
        Get
            'If index <> -1 Then
            Return CType(innerCol(index), Box)
            'End If
            'Return Nothing
        End Get
        Set(ByVal Value As Box)
            innerCol(index) = Value
        End Set
    End Property

    ' Determines if an item is in the collection
    ' by using the BoxSameDimensions equality comparer.
    Public Function Contains(ByVal item As Box) As Boolean _
            Implements ICollection(Of Box).Contains
        Dim found As Boolean = False

        Dim bx As Box
        For Each bx In innerCol
            If New BoxSameDimensions().Equals(bx, item) Then
                found = True
            End If
        Next

        Return found
    End Function

    ' Determines if an item is in the 
    ' collection by using a specified equality comparer.
    Public Function Contains(ByVal item As Box, _
        ByVal comp As EqualityComparer(Of Box)) As Boolean
        Dim found As Boolean = False

        Dim bx As Box
        For Each bx In innerCol
            If comp.Equals(bx, item) Then
                found = True
            End If
        Next

        Return found
    End Function

    ' Adds an item if it is not already in the collection
    ' as determined by calling the Contains method.
    Public Sub Add(ByVal item As Box) _
        Implements ICollection(Of Box).Add

        If Not Me.Contains(item) Then
            innerCol.Add(item)
        Else
            Console.WriteLine("A box with {0}x{1}x{2} dimensions was already added to the collection.",
                item.Height.ToString(), item.Length.ToString(), item.Width.ToString())
        End If
    End Sub

    Public Sub Clear() Implements ICollection(Of Box).Clear
        innerCol.Clear()
    End Sub

    Public Sub CopyTo(array As Box(), arrayIndex As Integer) _
            Implements ICollection(Of Box).CopyTo
        If array Is Nothing Then
           Throw New ArgumentNullException("The array cannot be null.")
        Else If arrayIndex < 0 Then
           Throw New ArgumentOutOfRangeException("The starting array index cannot be negative.")
        Else If Count > array.Length - arrayIndex + 1 Then
           Throw New ArgumentException("The destination array has fewer elements than the collection.")
        End If
        
        For i As Integer = 0 To innerCol.Count - 1
            array(i + arrayIndex) = innerCol(i)
        Next
    End Sub

    Public ReadOnly Property Count() As Integer _
            Implements ICollection(Of Box).Count
        Get
            Return innerCol.Count
        End Get
    End Property

    Public ReadOnly Property IsReadOnly() As Boolean _
           Implements ICollection(Of Box).IsReadOnly
        Get
            Return False
        End Get
    End Property

    Public Function Remove(ByVal item As Box) As Boolean _
            Implements ICollection(Of Box).Remove
        Dim result As Boolean = False

        ' Iterate the inner collection to 
        ' find the box to be removed.

        Dim i As Integer
        For i = 0 To innerCol.Count - 1

            Dim curBox As Box = CType(innerCol(i), Box)

            If New BoxSameDimensions().Equals(curBox, item) Then
                innerCol.RemoveAt(i)
                result = True
                Exit For
            End If
        Next
        Return result
    End Function
End Class

' Defines the enumerator for the Boxes collection.
' (Some prefer this class nested in the collection class.)
Public Class BoxEnumerator
    Implements IEnumerator(Of Box)
    Private _collection As BoxCollection
    Private curIndex As Integer
    Private curBox As Box


    Public Sub New(ByVal collection As BoxCollection)
        MyBase.New()
        _collection = collection
        curIndex = -1
        curBox = Nothing

    End Sub

    Private Property Box As Box
    Public Function MoveNext() As Boolean _
        Implements IEnumerator(Of Box).MoveNext
        curIndex = curIndex + 1
        If curIndex = _collection.Count Then
            ' Avoids going beyond the end of the collection.
            Return False
        Else
            'Set current box to next item in collection.
            curBox = _collection(curIndex)
        End If
        Return True
    End Function

    Public Sub Reset() _
        Implements IEnumerator(Of Box).Reset
        curIndex = -1
    End Sub

    Public Sub Dispose() _
        Implements IEnumerator(Of Box).Dispose

    End Sub

    Public ReadOnly Property Current() As Box _
        Implements IEnumerator(Of Box).Current

        Get
            If curBox Is Nothing Then
                Throw New InvalidOperationException()
            End If

            Return curBox
        End Get
    End Property

    Private ReadOnly Property Current1() As Object _
        Implements IEnumerator.Current

        Get
            Return Me.Current
        End Get
    End Property
End Class

' Defines two boxes as equal if they have the same dimensions.
Public Class BoxSameDimensions
    Inherits EqualityComparer(Of Box)

    Public Overrides Function Equals(ByVal b1 As Box, ByVal b2 As Box) As Boolean
        If b1.Height = b2.Height And b1.Length = b2.Length And b1.Width = b2.Width Then
            Return True
        Else
            Return False
        End If
    End Function

    Public Overrides Function GetHashCode(ByVal bx As Box) As Integer
        Dim hCode As Integer = bx.Height ^ bx.Length ^ bx.Width
        Return hCode.GetHashCode()
    End Function
End Class

' Defines two boxes as equal if they have the same volume.
Public Class BoxSameVol
    Inherits EqualityComparer(Of Box)

    Public Overrides Function Equals(ByVal b1 As Box, ByVal b2 As Box) As Boolean
        If (b1.Height * b1.Length * b1.Width) _
            = (b2.Height * b2.Length * b2.Width) Then
            Return True
        Else
            Return False
        End If
    End Function

    Public Overrides Function GetHashCode(ByVal bx As Box) As Integer
        Dim hCode As Integer = bx.Height ^ bx.Length ^ bx.Width
        Console.WriteLine("HC: {0}", hCode.GetHashCode())
        Return hCode.GetHashCode()
    End Function
End Class


'  This code example displays the following output:
'  ================================================
'
'  A box with 10x4x6 dimensions was already added to the collection.
'
'  Height  Length  Width   Hash Code
'  10      4       6       46104728
'  4       6       10      12289376
'  6       10      4       43495525
'  12      8       10      55915408
'
'  Removing 6x10x4
'
'  Height  Length  Width   Hash Code
'  10      4       6       46104728
'  4       6       10      12289376
'  12      8       10      55915408
'
'  Contains 8x12x10 by dimensions: False
'  Contains 8x12x10 by volume: True
'

Remarks

The ICollection<T> interface is the base interface for classes in the System.Collections.Generic namespace.

The ICollection<T> interface extends IEnumerable<T>; IDictionary<TKey,TValue> and IList<T> are more specialized interfaces that extend ICollection<T>. A IDictionary<TKey,TValue> implementation is a collection of key/value pairs, like the Dictionary<TKey,TValue> class. A IList<T> implementation is a collection of values, and its members can be accessed by index, like the List<T> class.

If neither the IDictionary<TKey,TValue> interface nor the IList<T> interface meet the requirements of the required collection, derive the new collection class from the ICollection<T> interface instead for more flexibility.

Properties

Count	Gets the number of elements contained in the ICollection<T>.
IsReadOnly	Gets a value indicating whether the ICollection<T> is read-only.

Methods

Add(T)	Adds an item to the ICollection<T>.
Clear()	Removes all items from the ICollection<T>.
Contains(T)	Determines whether the ICollection<T> contains a specific value.
CopyTo(T[], Int32)	Copies the elements of the ICollection<T> to an Array, starting at a particular Array index.
GetEnumerator()	Returns an enumerator that iterates through a collection. (Inherited from IEnumerable)
Remove(T)	Removes the first occurrence of a specific object from the ICollection<T>.

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.
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>.
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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