List<T> Class
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List<T> Class
- Reference
Definition
Represents a strongly typed list of objects that can be accessed by index. Provides methods to search, sort, and manipulate lists.
generic <typename T>
public ref class List : 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::Collections::IListgeneric <typename T>
public ref class List : System::Collections::Generic::ICollection<T>, System::Collections::Generic::IEnumerable<T>, System::Collections::Generic::IList<T>, System::Collections::IListpublic class List<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.Collections.IList[System.Serializable]
public class List<T> : System.Collections.Generic.ICollection<T>, System.Collections.Generic.IEnumerable<T>, System.Collections.Generic.IList<T>, System.Collections.IList[System.Serializable]
public class List<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.Collections.IListtype List<'T> = class
interface ICollection<'T>
interface seq<'T>
interface IEnumerable
interface IList<'T>
interface IReadOnlyCollection<'T>
interface IReadOnlyList<'T>
interface ICollection
interface IList[<System.Serializable>]
type List<'T> = class
interface IList<'T>
interface ICollection<'T>
interface seq<'T>
interface IList
interface ICollection
interface IEnumerable[<System.Serializable>]
type List<'T> = class
interface IList<'T>
interface ICollection<'T>
interface IList
interface ICollection
interface IReadOnlyList<'T>
interface IReadOnlyCollection<'T>
interface seq<'T>
interface IEnumerable[<System.Serializable>]
type List<'T> = class
interface IList<'T>
interface ICollection<'T>
interface seq<'T>
interface IEnumerable
interface IList
interface ICollection
interface IReadOnlyList<'T>
interface IReadOnlyCollection<'T>type List<'T> = class
interface IList<'T>
interface ICollection<'T>
interface IReadOnlyList<'T>
interface IReadOnlyCollection<'T>
interface seq<'T>
interface IList
interface ICollection
interface IEnumerable[<System.Serializable>]
type List<'T> = class
interface IList<'T>
interface IList
interface IReadOnlyList<'T>
interface ICollection<'T>
interface seq<'T>
interface IEnumerable
interface ICollection
interface IReadOnlyCollection<'T>Public Class List(Of T)
Implements ICollection(Of T), IEnumerable(Of T), IList, IList(Of T), IReadOnlyCollection(Of T), IReadOnlyList(Of T)Public Class List(Of T)
Implements ICollection(Of T), IEnumerable(Of T), IList, IList(Of T)Type Parameters
The type of elements in the list.
Examples
The following example demonstrates how to add, remove, and insert a simple business object in a List<T>.
using System;
using System.Collections.Generic;
// Simple business object. A PartId is used to identify the type of part
// but the part name can change.
public class Part : IEquatable<Part>
{
public string PartName { get; set; }
public int PartId { get; set; }
public override string ToString()
{
return "ID: " + PartId + " Name: " + PartName;
}
public override bool Equals(object obj)
{
if (obj == null) return false;
Part objAsPart = obj as Part;
if (objAsPart == null) return false;
else return Equals(objAsPart);
}
public override int GetHashCode()
{
return PartId;
}
public bool Equals(Part other)
{
if (other == null) return false;
return (this.PartId.Equals(other.PartId));
}
// Should also override == and != operators.
}
public class Example
{
public static void Main()
{
// Create a list of parts.
List<Part> parts = new List<Part>();
// Add parts to the list.
parts.Add(new Part() { PartName = "crank arm", PartId = 1234 });
parts.Add(new Part() { PartName = "chain ring", PartId = 1334 });
parts.Add(new Part() { PartName = "regular seat", PartId = 1434 });
parts.Add(new Part() { PartName = "banana seat", PartId = 1444 });
parts.Add(new Part() { PartName = "cassette", PartId = 1534 });
parts.Add(new Part() { PartName = "shift lever", PartId = 1634 });
// Write out the parts in the list. This will call the overridden ToString method
// in the Part class.
Console.WriteLine();
foreach (Part aPart in parts)
{
Console.WriteLine(aPart);
}
// Check the list for part #1734. This calls the IEquatable.Equals method
// of the Part class, which checks the PartId for equality.
Console.WriteLine("\nContains(\"1734\"): {0}",
parts.Contains(new Part { PartId = 1734, PartName = "" }));
// Insert a new item at position 2.
Console.WriteLine("\nInsert(2, \"1834\")");
parts.Insert(2, new Part() { PartName = "brake lever", PartId = 1834 });
//Console.WriteLine();
foreach (Part aPart in parts)
{
Console.WriteLine(aPart);
}
Console.WriteLine("\nParts[3]: {0}", parts[3]);
Console.WriteLine("\nRemove(\"1534\")");
// This will remove part 1534 even though the PartName is different,
// because the Equals method only checks PartId for equality.
parts.Remove(new Part() { PartId = 1534, PartName = "cogs" });
Console.WriteLine();
foreach (Part aPart in parts)
{
Console.WriteLine(aPart);
}
Console.WriteLine("\nRemoveAt(3)");
// This will remove the part at index 3.
parts.RemoveAt(3);
Console.WriteLine();
foreach (Part aPart in parts)
{
Console.WriteLine(aPart);
}
/*
ID: 1234 Name: crank arm
ID: 1334 Name: chain ring
ID: 1434 Name: regular seat
ID: 1444 Name: banana seat
ID: 1534 Name: cassette
ID: 1634 Name: shift lever
Contains("1734"): False
Insert(2, "1834")
ID: 1234 Name: crank arm
ID: 1334 Name: chain ring
ID: 1834 Name: brake lever
ID: 1434 Name: regular seat
ID: 1444 Name: banana seat
ID: 1534 Name: cassette
ID: 1634 Name: shift lever
Parts[3]: ID: 1434 Name: regular seat
Remove("1534")
ID: 1234 Name: crank arm
ID: 1334 Name: chain ring
ID: 1834 Name: brake lever
ID: 1434 Name: regular seat
ID: 1444 Name: banana seat
ID: 1634 Name: shift lever
RemoveAt(3)
ID: 1234 Name: crank arm
ID: 1334 Name: chain ring
ID: 1834 Name: brake lever
ID: 1444 Name: banana seat
ID: 1634 Name: shift lever
*/
}
}
Imports System.Collections.Generic
' Simple business object. A PartId is used to identify the type of part
' but the part name can change.
Public Class Part
Implements IEquatable(Of Part)
Public Property PartName() As String
Get
Return m_PartName
End Get
Set(value As String)
m_PartName = Value
End Set
End Property
Private m_PartName As String
Public Property PartId() As Integer
Get
Return m_PartId
End Get
Set(value As Integer)
m_PartId = Value
End Set
End Property
Private m_PartId As Integer
Public Overrides Function ToString() As String
Return "ID: " & PartId & " Name: " & PartName
End Function
Public Overrides Function Equals(obj As Object) As Boolean
If obj Is Nothing Then
Return False
End If
Dim objAsPart As Part = TryCast(obj, Part)
If objAsPart Is Nothing Then
Return False
Else
Return Equals(objAsPart)
End If
End Function
Public Overrides Function GetHashCode() As Integer
Return PartId
End Function
Public Overloads Function Equals(other As Part) As Boolean _
Implements IEquatable(Of Part).Equals
If other Is Nothing Then
Return False
End If
Return (Me.PartId.Equals(other.PartId))
End Function
' Should also override == and != operators.
End Class
Public Class Example
Public Shared Sub Main()
' Create a list of parts.
Dim parts As New List(Of Part)()
' Add parts to the list.
parts.Add(New Part() With { _
.PartName = "crank arm", _
.PartId = 1234 _
})
parts.Add(New Part() With { _
.PartName = "chain ring", _
.PartId = 1334 _
})
parts.Add(New Part() With { _
.PartName = "regular seat", _
.PartId = 1434 _
})
parts.Add(New Part() With { _
.PartName = "banana seat", _
.PartId = 1444 _
})
parts.Add(New Part() With { _
.PartName = "cassette", _
.PartId = 1534 _
})
parts.Add(New Part() With { _
.PartName = "shift lever", _
.PartId = 1634 _
})
' Write out the parts in the list. This will call the overridden ToString method
' in the Part class.
Console.WriteLine()
For Each aPart As Part In parts
Console.WriteLine(aPart)
Next
' Check the list for part #1734. This calls the IEquatable.Equals method
' of the Part class, which checks the PartId for equality.
Console.WriteLine(vbLf & "Contains(""1734""): {0}", parts.Contains(New Part() With { _
.PartId = 1734, _
.PartName = "" _
}))
' Insert a new item at position 2.
Console.WriteLine(vbLf & "Insert(2, ""1834"")")
parts.Insert(2, New Part() With { _
.PartName = "brake lever", _
.PartId = 1834 _
})
'Console.WriteLine();
For Each aPart As Part In parts
Console.WriteLine(aPart)
Next
Console.WriteLine(vbLf & "Parts[3]: {0}", parts(3))
Console.WriteLine(vbLf & "Remove(""1534"")")
' This will remove part 1534 even though the PartName is different,
' because the Equals method only checks PartId for equality.
parts.Remove(New Part() With { _
.PartId = 1534, _
.PartName = "cogs" _
})
Console.WriteLine()
For Each aPart As Part In parts
Console.WriteLine(aPart)
Next
Console.WriteLine(vbLf & "RemoveAt(3)")
' This will remove part at index 3.
parts.RemoveAt(3)
Console.WriteLine()
For Each aPart As Part In parts
Console.WriteLine(aPart)
Next
End Sub
'
' This example code produces the following output:
' ID: 1234 Name: crank arm
' ID: 1334 Name: chain ring
' ID: 1434 Name: regular seat
' ID: 1444 Name: banana seat
' ID: 1534 Name: cassette
' ID: 1634 Name: shift lever
'
' Contains("1734"): False
'
' Insert(2, "1834")
' ID: 1234 Name: crank arm
' ID: 1334 Name: chain ring
' ID: 1834 Name: brake lever
' ID: 1434 Name: regular seat
' ID: 1444 Name: banana seat
' ID: 1534 Name: cassette
' ID: 1634 Name: shift lever
'
' Parts[3]: ID: 1434 Name: regular seat
'
' Remove("1534")
'
' ID: 1234 Name: crank arm
' ID: 1334 Name: chain ring
' ID: 1834 Name: brake lever
' ID: 1434 Name: regular seat
' ID: 1444 Name: banana seat
' ID: 1634 Name: shift lever
' '
' RemoveAt(3)
'
' ID: 1234 Name: crank arm
' ID: 1334 Name: chain ring
' ID: 1834 Name: brake lever
' ID: 1444 Name: banana seat
' ID: 1634 Name: shift lever
'
End Class
// Simple business object. A PartId is used to identify the type of part
// but the part name can change.
[<CustomEquality; NoComparison>]
type Part = { PartId : int ; mutable PartName : string } with
override this.GetHashCode() = hash this.PartId
override this.Equals(other) =
match other with
| :? Part as p -> this.PartId = p.PartId
| _ -> false
override this.ToString() = sprintf "ID: %i Name: %s" this.PartId this.PartName
[<EntryPoint>]
let main argv =
// We refer to System.Collections.Generic.List<'T> by its type
// abbreviation ResizeArray<'T> to avoid conflicts with the F# List module.
// Note: In F# code, F# linked lists are usually preferred over
// ResizeArray<'T> when an extendable collection is required.
let parts = ResizeArray<_>()
parts.Add({PartName = "crank arm" ; PartId = 1234})
parts.Add({PartName = "chain ring"; PartId = 1334 })
parts.Add({PartName = "regular seat"; PartId = 1434 })
parts.Add({PartName = "banana seat"; PartId = 1444 })
parts.Add({PartName = "cassette"; PartId = 1534 })
parts.Add({PartName = "shift lever"; PartId = 1634 })
// Write out the parts in the ResizeArray. This will call the overridden ToString method
// in the Part type
printfn ""
parts |> Seq.iter (fun p -> printfn "%O" p)
// Check the ResizeArray for part #1734. This calls the IEquatable.Equals method
// of the Part type, which checks the PartId for equality.
printfn "\nContains(\"1734\"): %b" (parts.Contains({PartId=1734; PartName=""}))
// Insert a new item at position 2.
printfn "\nInsert(2, \"1834\")"
parts.Insert(2, { PartName = "brake lever"; PartId = 1834 })
// Write out all parts
parts |> Seq.iter (fun p -> printfn "%O" p)
printfn "\nParts[3]: %O" parts.[3]
printfn "\nRemove(\"1534\")"
// This will remove part 1534 even though the PartName is different,
// because the Equals method only checks PartId for equality.
// Since Remove returns true or false, we need to ignore the result
parts.Remove({PartId=1534; PartName="cogs"}) |> ignore
// Write out all parts
printfn ""
parts |> Seq.iter (fun p -> printfn "%O" p)
printfn "\nRemoveAt(3)"
// This will remove the part at index 3.
parts.RemoveAt(3)
// Write out all parts
printfn ""
parts |> Seq.iter (fun p -> printfn "%O" p)
0 // return an integer exit code
The following example demonstrates several properties and methods of the List<T> generic class of type string. (For an example of a List<T> of complex types, see the Contains method.)
The parameterless constructor is used to create a list of strings with the default capacity. The Capacity property is displayed and then the Add method is used to add several items. The items are listed, and the Capacity property is displayed again, along with the Count property, to show that the capacity has been increased as needed.
The Contains method is used to test for the presence of an item in the list, the Insert method is used to insert a new item in the middle of the list, and the contents of the list are displayed again.
The default Item[] property (the indexer in C#) is used to retrieve an item, the Remove method is used to remove the first instance of the duplicate item added earlier, and the contents are displayed again. The Remove method always removes the first instance it encounters.
The TrimExcess method is used to reduce the capacity to match the count, and the Capacity and Count properties are displayed. If the unused capacity had been less than 10 percent of total capacity, the list would not have been resized.
Finally, the Clear method is used to remove all items from the list, and the Capacity and Count properties are displayed.
using namespace System;
using namespace System::Collections::Generic;
void main()
{
List<String^>^ dinosaurs = gcnew List<String^>();
Console::WriteLine("\nCapacity: {0}", dinosaurs->Capacity);
dinosaurs->Add("Tyrannosaurus");
dinosaurs->Add("Amargasaurus");
dinosaurs->Add("Mamenchisaurus");
dinosaurs->Add("Deinonychus");
dinosaurs->Add("Compsognathus");
Console::WriteLine();
for each(String^ dinosaur in dinosaurs )
{
Console::WriteLine(dinosaur);
}
Console::WriteLine("\nCapacity: {0}", dinosaurs->Capacity);
Console::WriteLine("Count: {0}", dinosaurs->Count);
Console::WriteLine("\nContains(\"Deinonychus\"): {0}",
dinosaurs->Contains("Deinonychus"));
Console::WriteLine("\nInsert(2, \"Compsognathus\")");
dinosaurs->Insert(2, "Compsognathus");
Console::WriteLine();
for each(String^ dinosaur in dinosaurs )
{
Console::WriteLine(dinosaur);
}
Console::WriteLine("\ndinosaurs[3]: {0}", dinosaurs[3]);
Console::WriteLine("\nRemove(\"Compsognathus\")");
dinosaurs->Remove("Compsognathus");
Console::WriteLine();
for each(String^ dinosaur in dinosaurs )
{
Console::WriteLine(dinosaur);
}
dinosaurs->TrimExcess();
Console::WriteLine("\nTrimExcess()");
Console::WriteLine("Capacity: {0}", dinosaurs->Capacity);
Console::WriteLine("Count: {0}", dinosaurs->Count);
dinosaurs->Clear();
Console::WriteLine("\nClear()");
Console::WriteLine("Capacity: {0}", dinosaurs->Capacity);
Console::WriteLine("Count: {0}", dinosaurs->Count);
}
/* This code example produces the following output:
Capacity: 0
Tyrannosaurus
Amargasaurus
Mamenchisaurus
Deinonychus
Compsognathus
Capacity: 8
Count: 5
Contains("Deinonychus"): True
Insert(2, "Compsognathus")
Tyrannosaurus
Amargasaurus
Compsognathus
Mamenchisaurus
Deinonychus
Compsognathus
dinosaurs[3]: Mamenchisaurus
Remove("Compsognathus")
Tyrannosaurus
Amargasaurus
Mamenchisaurus
Deinonychus
Compsognathus
TrimExcess()
Capacity: 5
Count: 5
Clear()
Capacity: 5
Count: 0
*/
List<string> dinosaurs = new List<string>();
Console.WriteLine("\nCapacity: {0}", dinosaurs.Capacity);
dinosaurs.Add("Tyrannosaurus");
dinosaurs.Add("Amargasaurus");
dinosaurs.Add("Mamenchisaurus");
dinosaurs.Add("Deinonychus");
dinosaurs.Add("Compsognathus");
Console.WriteLine();
foreach(string dinosaur in dinosaurs)
{
Console.WriteLine(dinosaur);
}
Console.WriteLine("\nCapacity: {0}", dinosaurs.Capacity);
Console.WriteLine("Count: {0}", dinosaurs.Count);
Console.WriteLine("\nContains(\"Deinonychus\"): {0}",
dinosaurs.Contains("Deinonychus"));
Console.WriteLine("\nInsert(2, \"Compsognathus\")");
dinosaurs.Insert(2, "Compsognathus");
Console.WriteLine();
foreach(string dinosaur in dinosaurs)
{
Console.WriteLine(dinosaur);
}
// Shows accessing the list using the Item property.
Console.WriteLine("\ndinosaurs[3]: {0}", dinosaurs[3]);
Console.WriteLine("\nRemove(\"Compsognathus\")");
dinosaurs.Remove("Compsognathus");
Console.WriteLine();
foreach(string dinosaur in dinosaurs)
{
Console.WriteLine(dinosaur);
}
dinosaurs.TrimExcess();
Console.WriteLine("\nTrimExcess()");
Console.WriteLine("Capacity: {0}", dinosaurs.Capacity);
Console.WriteLine("Count: {0}", dinosaurs.Count);
dinosaurs.Clear();
Console.WriteLine("\nClear()");
Console.WriteLine("Capacity: {0}", dinosaurs.Capacity);
Console.WriteLine("Count: {0}", dinosaurs.Count);
/* This code example produces the following output:
Capacity: 0
Tyrannosaurus
Amargasaurus
Mamenchisaurus
Deinonychus
Compsognathus
Capacity: 8
Count: 5
Contains("Deinonychus"): True
Insert(2, "Compsognathus")
Tyrannosaurus
Amargasaurus
Compsognathus
Mamenchisaurus
Deinonychus
Compsognathus
dinosaurs[3]: Mamenchisaurus
Remove("Compsognathus")
Tyrannosaurus
Amargasaurus
Mamenchisaurus
Deinonychus
Compsognathus
TrimExcess()
Capacity: 5
Count: 5
Clear()
Capacity: 5
Count: 0
*/
Imports System.Collections.Generic
Public Class Example
Public Shared Sub Main()
Dim dinosaurs As New List(Of String)
Console.WriteLine(vbLf & "Capacity: {0}", dinosaurs.Capacity)
dinosaurs.Add("Tyrannosaurus")
dinosaurs.Add("Amargasaurus")
dinosaurs.Add("Mamenchisaurus")
dinosaurs.Add("Deinonychus")
dinosaurs.Add("Compsognathus")
Console.WriteLine()
For Each dinosaur As String In dinosaurs
Console.WriteLine(dinosaur)
Next
Console.WriteLine(vbLf & "Capacity: {0}", dinosaurs.Capacity)
Console.WriteLine("Count: {0}", dinosaurs.Count)
Console.WriteLine(vbLf & "Contains(""Deinonychus""): {0}", _
dinosaurs.Contains("Deinonychus"))
Console.WriteLine(vbLf & "Insert(2, ""Compsognathus"")")
dinosaurs.Insert(2, "Compsognathus")
Console.WriteLine()
For Each dinosaur As String In dinosaurs
Console.WriteLine(dinosaur)
Next
' Shows how to access the list using the Item property.
Console.WriteLine(vbLf & "dinosaurs(3): {0}", dinosaurs(3))
Console.WriteLine(vbLf & "Remove(""Compsognathus"")")
dinosaurs.Remove("Compsognathus")
Console.WriteLine()
For Each dinosaur As String In dinosaurs
Console.WriteLine(dinosaur)
Next
dinosaurs.TrimExcess()
Console.WriteLine(vbLf & "TrimExcess()")
Console.WriteLine("Capacity: {0}", dinosaurs.Capacity)
Console.WriteLine("Count: {0}", dinosaurs.Count)
dinosaurs.Clear()
Console.WriteLine(vbLf & "Clear()")
Console.WriteLine("Capacity: {0}", dinosaurs.Capacity)
Console.WriteLine("Count: {0}", dinosaurs.Count)
End Sub
End Class
' This code example produces the following output:
'
'Capacity: 0
'
'Tyrannosaurus
'Amargasaurus
'Mamenchisaurus
'Deinonychus
'Compsognathus
'
'Capacity: 8
'Count: 5
'
'Contains("Deinonychus"): True
'
'Insert(2, "Compsognathus")
'
'Tyrannosaurus
'Amargasaurus
'Compsognathus
'Mamenchisaurus
'Deinonychus
'Compsognathus
'
'dinosaurs(3): Mamenchisaurus
'
'Remove("Compsognathus")
'
'Tyrannosaurus
'Amargasaurus
'Mamenchisaurus
'Deinonychus
'Compsognathus
'
'TrimExcess()
'Capacity: 5
'Count: 5
'
'Clear()
'Capacity: 5
'Count: 0
[<EntryPoint>]
let main argv =
// We refer to System.Collections.Generic.List<'T> by its type
// abbreviation ResizeArray<'T> to avoid conflict with the List module.
// Note: In F# code, F# linked lists are usually preferred over
// ResizeArray<'T> when an extendable collection is required.
let dinosaurs = ResizeArray<_>()
// Write out the dinosaurs in the ResizeArray.
let printDinosaurs() =
printfn ""
dinosaurs |> Seq.iter (fun p -> printfn "%O" p)
printfn "\nCapacity: %i" dinosaurs.Capacity
dinosaurs.Add("Tyrannosaurus")
dinosaurs.Add("Amargasaurus")
dinosaurs.Add("Mamenchisaurus")
dinosaurs.Add("Deinonychus")
dinosaurs.Add("Compsognathus")
printDinosaurs()
printfn "\nCapacity: %i" dinosaurs.Capacity
printfn "Count: %i" dinosaurs.Count
printfn "\nContains(\"Deinonychus\"): %b" (dinosaurs.Contains("Deinonychus"))
printfn "\nInsert(2, \"Compsognathus\")"
dinosaurs.Insert(2, "Compsognathus")
printDinosaurs()
// Shows accessing the list using the Item property.
printfn "\ndinosaurs[3]: %s" dinosaurs.[3]
printfn "\nRemove(\"Compsognathus\")"
dinosaurs.Remove("Compsognathus") |> ignore
printDinosaurs()
dinosaurs.TrimExcess()
printfn "\nTrimExcess()"
printfn "Capacity: %i" dinosaurs.Capacity
printfn "Count: %i" dinosaurs.Count
dinosaurs.Clear()
printfn "\nClear()"
printfn "Capacity: %i" dinosaurs.Capacity
printfn "Count: %i" dinosaurs.Count
0 // return an integer exit code
(* This code example produces the following output:
Capacity: 0
Tyrannosaurus
Amargasaurus
Mamenchisaurus
Deinonychus
Compsognathus
Capacity: 8
Count: 5
Contains("Deinonychus"): true
Insert(2, "Compsognathus")
Tyrannosaurus
Amargasaurus
Compsognathus
Mamenchisaurus
Deinonychus
Compsognathus
dinosaurs[3]: Mamenchisaurus
Remove("Compsognathus")
Tyrannosaurus
Amargasaurus
Mamenchisaurus
Deinonychus
Compsognathus
TrimExcess()
Capacity: 5
Count: 5
Clear()
Capacity: 5
Count: 0
*)
Remarks
The List<T> class is the generic equivalent of the ArrayList class. It implements the IList<T> generic interface by using an array whose size is dynamically increased as required.
You can add items to a List<T> by using the Add or AddRange methods.
The List<T> class uses both an equality comparer and an ordering comparer.
Methods such as Contains, IndexOf, LastIndexOf, and Remove use an equality comparer for the list elements. The default equality comparer for type
Tis determined as follows. If typeTimplements the IEquatable<T> generic interface, then the equality comparer is the Equals(T) method of that interface; otherwise, the default equality comparer is Object.Equals(Object).Methods such as BinarySearch and Sort use an ordering comparer for the list elements. The default comparer for type
Tis determined as follows. If typeTimplements the IComparable<T> generic interface, then the default comparer is the CompareTo(T) method of that interface; otherwise, if typeTimplements the nongeneric IComparable interface, then the default comparer is the CompareTo(Object) method of that interface. If typeTimplements neither interface, then there is no default comparer, and a comparer or comparison delegate must be provided explicitly.
The List<T> is not guaranteed to be sorted. You must sort the List<T> before performing operations (such as BinarySearch) that require the List<T> to be sorted.
Elements in this collection can be accessed using an integer index. Indexes in this collection are zero-based.
.NET Framework only: For very large List<T> objects, you can increase the maximum capacity to 2 billion elements on a 64-bit system by setting the enabled attribute of the <gcAllowVeryLargeObjects> configuration element to true in the run-time environment.
List<T> accepts null as a valid value for reference types and allows duplicate elements.
For an immutable version of the List<T> class, see ImmutableList<T>.
Performance Considerations
In deciding whether to use the List<T> or ArrayList class, both of which have similar functionality, remember that the List<T> class performs better in most cases and is type safe. If a reference type is used for type T of the List<T> class, the behavior of the two classes is identical. However, if a value type is used for type T, you need to consider implementation and boxing issues.
If a value type is used for type T, the compiler generates an implementation of the List<T> class specifically for that value type. That means a list element of a List<T> object does not have to be boxed before the element can be used, and after about 500 list elements are created, the memory saved by not boxing list elements is greater than the memory used to generate the class implementation.
Make certain the value type used for type T implements the IEquatable<T> generic interface. If not, methods such as Contains must call the Object.Equals(Object) method, which boxes the affected list element. If the value type implements the IComparable interface and you own the source code, also implement the IComparable<T> generic interface to prevent the BinarySearch and Sort methods from boxing list elements. If you do not own the source code, pass an IComparer<T> object to the BinarySearch and Sort methods
It is to your advantage to use the type-specific implementation of the List<T> class instead of using the ArrayList class or writing a strongly typed wrapper collection yourself. That's because your implementation must do what the .NET Framework does for you already, and the common language runtime can share Microsoft intermediate language code and metadata, which your implementation cannot.
F# Considerations
The List<T> class is used infrequently in F# code. Instead, Lists, which are immutable, singly-linked lists, are typically preferred. An F# List provides an ordered, immutable series of values, and is supported for use in functional-style development. When used from F#, the List<T> class is typically referred to by the ResizeArray<'T> type abbreviation to avoid naming conflicts with F# Lists.
Constructors
Initializes a new instance of the List<T> class that is empty and has the default initial capacity.
Initializes a new instance of the List<T> class that contains elements copied from the specified collection and has sufficient capacity to accommodate the number of elements copied.
Initializes a new instance of the List<T> class that is empty and has the specified initial capacity.
Properties
Gets or sets the total number of elements the internal data structure can hold without resizing.
Gets the number of elements contained in the List<T>.
Gets or sets the element at the specified index.
Methods
Adds an object to the end of the List<T>.
Adds the elements of the specified collection to the end of the List<T>.
Returns a read-only ReadOnlyCollection<T> wrapper for the current collection.
BinarySearch(Int32, Int32, T, IComparer<T>)
Searches a range of elements in the sorted List<T> for an element using the specified comparer and returns the zero-based index of the element.
Searches the entire sorted List<T> for an element using the default comparer and returns the zero-based index of the element.
Searches the entire sorted List<T> for an element using the specified comparer and returns the zero-based index of the element.
Removes all elements from the List<T>.
Determines whether an element is in the List<T>.
ConvertAll<TOutput>(Converter<T,TOutput>)
Converts the elements in the current List<T> to another type, and returns a list containing the converted elements.
CopyTo(Int32, T[], Int32, Int32)
Copies a range of elements from the List<T> to a compatible one-dimensional array, starting at the specified index of the target array.
Copies the entire List<T> to a compatible one-dimensional array, starting at the beginning of the target array.
Copies the entire List<T> to a compatible one-dimensional array, starting at the specified index of the target array.
Ensures that the capacity of this list is at least the specified capacity. If the current capacity is less than capacity, it is successively increased to twice the current capacity until it is at least the specified capacity.
Determines whether the specified object is equal to the current object.
(Inherited from Object) Exists(Predicate<T>)
Determines whether the List<T> contains elements that match the conditions defined by the specified predicate.
Searches for an element that matches the conditions defined by the specified predicate, and returns the first occurrence within the entire List<T>.
Retrieves all the elements that match the conditions defined by the specified predicate.
FindIndex(Int32, Int32, Predicate<T>)
Searches for an element that matches the conditions defined by the specified predicate, and returns the zero-based index of the first occurrence within the range of elements in the List<T> that starts at the specified index and contains the specified number of elements.
FindIndex(Int32, Predicate<T>)
Searches for an element that matches the conditions defined by the specified predicate, and returns the zero-based index of the first occurrence within the range of elements in the List<T> that extends from the specified index to the last element.
Searches for an element that matches the conditions defined by the specified predicate, and returns the zero-based index of the first occurrence within the entire List<T>.
Searches for an element that matches the conditions defined by the specified predicate, and returns the last occurrence within the entire List<T>.
FindLastIndex(Int32, Int32, Predicate<T>)
Searches for an element that matches the conditions defined by the specified predicate, and returns the zero-based index of the last occurrence within the range of elements in the List<T> that contains the specified number of elements and ends at the specified index.
FindLastIndex(Int32, Predicate<T>)
Searches for an element that matches the conditions defined by the specified predicate, and returns the zero-based index of the last occurrence within the range of elements in the List<T> that extends from the first element to the specified index.
Searches for an element that matches the conditions defined by the specified predicate, and returns the zero-based index of the last occurrence within the entire List<T>.
Performs the specified action on each element of the List<T>.
Returns an enumerator that iterates through the List<T>.
Serves as the default hash function.
(Inherited from Object) GetRange(Int32, Int32)
Creates a shallow copy of a range of elements in the source List<T>.
Gets the Type of the current instance.
(Inherited from Object) IndexOf(T)
Searches for the specified object and returns the zero-based index of the first occurrence within the entire List<T>.
Searches for the specified object and returns the zero-based index of the first occurrence within the range of elements in the List<T> that extends from the specified index to the last element.
Searches for the specified object and returns the zero-based index of the first occurrence within the range of elements in the List<T> that starts at the specified index and contains the specified number of elements.
Inserts an element into the List<T> at the specified index.
InsertRange(Int32, IEnumerable<T>)
Inserts the elements of a collection into the List<T> at the specified index.
Searches for the specified object and returns the zero-based index of the last occurrence within the entire List<T>.
Searches for the specified object and returns the zero-based index of the last occurrence within the range of elements in the List<T> that extends from the first element to the specified index.
Searches for the specified object and returns the zero-based index of the last occurrence within the range of elements in the List<T> that contains the specified number of elements and ends at the specified index.
Creates a shallow copy of the current Object.
(Inherited from Object) Remove(T)
Removes the first occurrence of a specific object from the List<T>.
Removes all the elements that match the conditions defined by the specified predicate.
Removes the element at the specified index of the List<T>.
Removes a range of elements from the List<T>.
Reverses the order of the elements in the entire List<T>.
Reverses the order of the elements in the specified range.
Sorts the elements in the entire List<T> using the default comparer.
Sorts the elements in the entire List<T> using the specified Comparison<T>.
Sorts the elements in the entire List<T> using the specified comparer.
Sort(Int32, Int32, IComparer<T>)
Sorts the elements in a range of elements in List<T> using the specified comparer.
Copies the elements of the List<T> to a new array.
Returns a string that represents the current object.
(Inherited from Object) TrimExcess()
Sets the capacity to the actual number of elements in the List<T>, if that number is less than a threshold value.
Determines whether every element in the List<T> matches the conditions defined by the specified predicate.
Explicit Interface Implementations
ICollection.CopyTo(Array, Int32)
Copies the elements of the ICollection to an Array, starting at a particular Array index.
Gets a value indicating whether access to the ICollection is synchronized (thread safe).
Gets an object that can be used to synchronize access to the ICollection.
Gets a value indicating whether the ICollection<T> is read-only.
Returns an enumerator that iterates through a collection.
IEnumerable<T>.GetEnumerator()
Returns an enumerator that iterates through a collection.
Adds an item to the IList.
Determines whether the IList contains a specific value.
Determines the index of a specific item in the IList.
Inserts an item to the IList at the specified index.
Gets a value indicating whether the IList has a fixed size.
Gets a value indicating whether the IList is read-only.
Gets or sets the element at the specified index.
Removes the first occurrence of a specific object from the IList.
Extension Methods
ToImmutableArray<TSource>(IEnumerable<TSource>)
Creates an immutable array from the specified collection.
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.
Constructs an immutable dictionary based on some transformation of a sequence.
Enumerates and transforms a sequence, and produces an immutable dictionary of its contents.
Enumerates and transforms a sequence, and produces an immutable dictionary of its contents by using the specified key comparer.
Enumerates and transforms a sequence, and produces an immutable dictionary of its contents by using the specified key and value comparers.
ToImmutableHashSet<TSource>(IEnumerable<TSource>)
Enumerates a sequence and produces an immutable hash set 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.
ToImmutableList<TSource>(IEnumerable<TSource>)
Enumerates a sequence and produces an immutable list of its contents.
Enumerates and transforms a sequence, and produces an immutable sorted dictionary of its contents.
Enumerates and transforms a sequence, and produces an immutable sorted dictionary of its contents by using the specified key comparer.
Enumerates and transforms a sequence, and produces an immutable sorted dictionary of its contents by using the specified key and value comparers.
ToImmutableSortedSet<TSource>(IEnumerable<TSource>)
Enumerates a sequence and produces an immutable sorted set 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.
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.
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>, DataTable, LoadOption, FillErrorEventHandler)
Copies DataRow objects to the specified DataTable, 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.
Applies an accumulator function over a sequence. The specified seed value is used as the initial accumulator value.
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.
All<TSource>(IEnumerable<TSource>, Func<TSource,Boolean>)
Determines whether all elements of a sequence satisfy a condition.
Any<TSource>(IEnumerable<TSource>)
Determines whether a sequence contains any elements.
Any<TSource>(IEnumerable<TSource>, Func<TSource,Boolean>)
Determines whether any element of a sequence satisfies a condition.
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.
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)
Determines whether a sequence contains a specified element by using the default equality comparer.
Contains<TSource>(IEnumerable<TSource>, TSource, IEqualityComparer<TSource>)
Determines whether a sequence contains a specified element by using a specified IEqualityComparer<T>.
Count<TSource>(IEnumerable<TSource>)
Returns the number of elements in a sequence.
Count<TSource>(IEnumerable<TSource>, Func<TSource,Boolean>)
Returns a number that represents how many elements in the specified sequence satisfy a condition.
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.
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.
Distinct<TSource>(IEnumerable<TSource>)
Returns distinct elements from a sequence by using the default equality comparer to compare values.
Distinct<TSource>(IEnumerable<TSource>, IEqualityComparer<TSource>)
Returns distinct elements from a sequence by using a specified IEqualityComparer<T> to compare values.
DistinctBy<TSource,TKey>(IEnumerable<TSource>, Func<TSource,TKey>)
Returns distinct elements from a sequence according to a specified key selector function.
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.
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>)
Produces the set difference of two sequences by using the default equality comparer to compare values.
Except<TSource>(IEnumerable<TSource>, IEnumerable<TSource>, IEqualityComparer<TSource>)
Produces the set difference of two sequences by using the specified IEqualityComparer<T> to compare values.
ExceptBy<TSource,TKey>(IEnumerable<TSource>, IEnumerable<TKey>, Func<TSource,TKey>)
Produces the set difference of two sequences according to a specified key selector function.
Produces the set difference of two sequences according to a specified key selector function.
First<TSource>(IEnumerable<TSource>)
Returns the first element of a sequence.
First<TSource>(IEnumerable<TSource>, Func<TSource,Boolean>)
Returns the first element in a sequence that satisfies a specified condition.
FirstOrDefault<TSource>(IEnumerable<TSource>)
Returns the first element of a sequence, or a default value if the sequence contains no elements.
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>)
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>, 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.
GroupBy<TSource,TKey>(IEnumerable<TSource>, Func<TSource,TKey>)
Groups the elements of a sequence according to a specified key selector function.
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,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.
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.
Groups the elements of a sequence according to a specified key selector function and creates a result value from each group and its key.
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.
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.
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.
Correlates the elements of two sequences based on equality of keys and groups the results. The default equality comparer is used to compare keys.
Correlates the elements of two sequences based on key equality and groups the results. A specified IEqualityComparer<T> is used to compare keys.
Intersect<TSource>(IEnumerable<TSource>, IEnumerable<TSource>)
Produces the set intersection of two sequences by using the default equality comparer to compare values.
Intersect<TSource>(IEnumerable<TSource>, IEnumerable<TSource>, IEqualityComparer<TSource>)
Produces the set intersection of two sequences by using the specified IEqualityComparer<T> to compare values.
IntersectBy<TSource,TKey>(IEnumerable<TSource>, IEnumerable<TKey>, Func<TSource,TKey>)
Produces the set intersection of two sequences according to a specified key selector function.
Produces the set intersection of two sequences according to a specified key selector function.
Correlates the elements of two sequences based on matching keys. The default equality comparer is used to compare keys.
Correlates the elements of two sequences based on matching keys. A specified IEqualityComparer<T> is used to compare keys.
Last<TSource>(IEnumerable<TSource>)
Returns the last element of a sequence.
Last<TSource>(IEnumerable<TSource>, Func<TSource,Boolean>)
Returns the last element of a sequence that satisfies a specified condition.
LastOrDefault<TSource>(IEnumerable<TSource>)
Returns the last element of a sequence, or a default value if the sequence contains no elements.
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>)
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>, 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.
LongCount<TSource>(IEnumerable<TSource>)
Returns an Int64 that represents the total number of elements in a sequence.
LongCount<TSource>(IEnumerable<TSource>, Func<TSource,Boolean>)
Returns an Int64 that represents how many elements in a sequence satisfy a condition.
Max<TSource>(IEnumerable<TSource>)
Returns the maximum value in a generic 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,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>)
Returns the maximum value in a generic sequence according to a specified key selector function.
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.
Min<TSource>(IEnumerable<TSource>)
Returns the minimum value in a generic sequence.
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,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>)
Returns the minimum value in a generic sequence according to a specified key selector function.
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.
Filters the elements of an IEnumerable based on a specified type.
OrderBy<TSource,TKey>(IEnumerable<TSource>, Func<TSource,TKey>)
Sorts the elements of a sequence in ascending order according to a key.
OrderBy<TSource,TKey>(IEnumerable<TSource>, Func<TSource,TKey>, IComparer<TKey>)
Sorts the elements of a sequence in ascending 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.
OrderByDescending<TSource,TKey>(IEnumerable<TSource>, Func<TSource,TKey>, IComparer<TKey>)
Sorts the elements of a sequence in descending order by using a specified comparer.
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.
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.
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>)
Determines whether two sequences are equal by comparing the elements by using the default equality comparer for their type.
SequenceEqual<TSource>(IEnumerable<TSource>, IEnumerable<TSource>, IEqualityComparer<TSource>)
Determines whether two sequences are equal by comparing their elements by using a specified IEqualityComparer<T>.
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.
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.
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.
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>)
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>, 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.
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>)
Creates a Dictionary<TKey,TValue> from an IEnumerable<T> according to a specified key selector function.
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.
Creates a Dictionary<TKey,TValue> from an IEnumerable<T> according to specified key selector and element selector functions.
Creates a Dictionary<TKey,TValue> from an IEnumerable<T> according to a specified key selector function, a comparer, and an element selector function.
ToHashSet<TSource>(IEnumerable<TSource>)
Creates a HashSet<T> from an IEnumerable<T>.
ToHashSet<TSource>(IEnumerable<TSource>, IEqualityComparer<TSource>)
Creates a HashSet<T> from an IEnumerable<T> using the comparer to compare keys.
ToList<TSource>(IEnumerable<TSource>)
Creates a List<T> from an IEnumerable<T>.
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>(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,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.
Creates a Lookup<TKey,TElement> from an IEnumerable<T> according to a specified key selector function, a comparer and an element selector function.
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>)
Produces the set union of two sequences by using the default equality comparer.
Union<TSource>(IEnumerable<TSource>, IEnumerable<TSource>, IEqualityComparer<TSource>)
Produces the set union of two sequences by using a specified IEqualityComparer<T>.
UnionBy<TSource,TKey>(IEnumerable<TSource>, IEnumerable<TSource>, Func<TSource,TKey>)
Produces the set union of two sequences according to a specified key selector function.
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.
Enables parallelization of a query.
AsParallel<TSource>(IEnumerable<TSource>)
Enables parallelization of a query.
Converts an IEnumerable to an IQueryable.
AsQueryable<TElement>(IEnumerable<TElement>)
Converts a generic IEnumerable<T> to a generic IQueryable<T>.
Returns a collection of elements that contains the ancestors of every node in the source collection.
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.
DescendantNodes<T>(IEnumerable<T>)
Returns a collection of the descendant nodes of every document and element in the source collection.
Descendants<T>(IEnumerable<T>)
Returns a collection of elements that contains the descendant elements of every element and document 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.
Returns a collection of the child 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.
InDocumentOrder<T>(IEnumerable<T>)
Returns a collection of nodes that contains all nodes in the source collection, sorted in document order.
Returns a collection of the child nodes of every document and element in the source collection.
Removes every node in the source collection from its parent node.
Applies to
Thread Safety
Public static (Shared in Visual Basic) members of this type are thread safe. Any instance members are not guaranteed to be thread safe.
It is safe to perform multiple read operations on a List<T>, but issues can occur if the collection is modified while it's being read. To ensure thread safety, lock the collection during a read or write operation. To enable a collection to be accessed by multiple threads for reading and writing, you must implement your own synchronization. For collections with built-in synchronization, see the classes in the System.Collections.Concurrent namespace. For an inherently thread-safe alternative, see the ImmutableList<T> class.
See also
Recommend
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