Add List int to List int C#

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Initializes a new instance of the List class.

List[]

public: List[]; public List []; Public Sub New []

Examples

The following example demonstrates the parameterless constructor of the List generic class. The parameterless constructor creates a list with the default capacity, as demonstrated by displaying the Capacity property.

The example adds, inserts, and removes items, showing how the capacity changes as these methods are used.

using namespace System; using namespace System::Collections::Generic; void main[] { List^ dinosaurs = gcnew List[]; 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 dinosaurs = new List[]; 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 [] let main argv = // We refer to System.Collections.Generic.List to avoid conflict with the List module. // Note: In F# code, F# linked lists are usually preferred over // ResizeArray : seq Public Sub New [collection As IEnumerable[Of T]]

Parameters

Exceptions

Examples

The following example demonstrates the List constructor and various methods of the List class that act on ranges. An array of strings is created and passed to the constructor, populating the list with the elements of the array. The Capacity property is then displayed, to show that the initial capacity is exactly what is required to hold the input elements.

using namespace System; using namespace System::Collections::Generic; void main[] { array^ input = { "Brachiosaurus", "Amargasaurus", "Mamenchisaurus" }; List^ dinosaurs = gcnew List[[IEnumerable^] input]; Console::WriteLine["\nCapacity: {0}", dinosaurs->Capacity]; Console::WriteLine[]; for each[String^ dinosaur in dinosaurs ] { Console::WriteLine[dinosaur]; } Console::WriteLine["\nAddRange[dinosaurs]"]; dinosaurs->AddRange[dinosaurs]; Console::WriteLine[]; for each[String^ dinosaur in dinosaurs ] { Console::WriteLine[dinosaur]; } Console::WriteLine["\nRemoveRange[2, 2]"]; dinosaurs->RemoveRange[2, 2]; Console::WriteLine[]; for each[String^ dinosaur in dinosaurs ] { Console::WriteLine[dinosaur]; } input = gcnew array { "Tyrannosaurus", "Deinonychus", "Velociraptor"}; Console::WriteLine["\nInsertRange[3, [IEnumerable^] input]"]; dinosaurs->InsertRange[3, [IEnumerable^] input]; Console::WriteLine[]; for each[String^ dinosaur in dinosaurs ] { Console::WriteLine[dinosaur]; } Console::WriteLine["\noutput = dinosaurs->GetRange[2, 3]->ToArray[]"]; array^ output = dinosaurs->GetRange[2, 3]->ToArray[]; Console::WriteLine[]; for each[String^ dinosaur in output ] { Console::WriteLine[dinosaur]; } } /* This code example produces the following output: Capacity: 3 Brachiosaurus Amargasaurus Mamenchisaurus AddRange[dinosaurs] Brachiosaurus Amargasaurus Mamenchisaurus Brachiosaurus Amargasaurus Mamenchisaurus RemoveRange[2, 2] Brachiosaurus Amargasaurus Amargasaurus Mamenchisaurus InsertRange[3, [IEnumerable^] input] Brachiosaurus Amargasaurus Amargasaurus Tyrannosaurus Deinonychus Velociraptor Mamenchisaurus output = dinosaurs->GetRange[2, 3]->ToArray[] Amargasaurus Tyrannosaurus Deinonychus */ using System; using System.Collections.Generic; public class Example { public static void Main[] { string[] input = { "Brachiosaurus", "Amargasaurus", "Mamenchisaurus" }; List dinosaurs = new List[input]; Console.WriteLine["\nCapacity: {0}", dinosaurs.Capacity]; Console.WriteLine[]; foreach[ string dinosaur in dinosaurs ] { Console.WriteLine[dinosaur]; } Console.WriteLine["\nAddRange[dinosaurs]"]; dinosaurs.AddRange[dinosaurs]; Console.WriteLine[]; foreach[ string dinosaur in dinosaurs ] { Console.WriteLine[dinosaur]; } Console.WriteLine["\nRemoveRange[2, 2]"]; dinosaurs.RemoveRange[2, 2]; Console.WriteLine[]; foreach[ string dinosaur in dinosaurs ] { Console.WriteLine[dinosaur]; } input = new string[] { "Tyrannosaurus", "Deinonychus", "Velociraptor"}; Console.WriteLine["\nInsertRange[3, input]"]; dinosaurs.InsertRange[3, input]; Console.WriteLine[]; foreach[ string dinosaur in dinosaurs ] { Console.WriteLine[dinosaur]; } Console.WriteLine["\noutput = dinosaurs.GetRange[2, 3].ToArray[]"]; string[] output = dinosaurs.GetRange[2, 3].ToArray[]; Console.WriteLine[]; foreach[ string dinosaur in output ] { Console.WriteLine[dinosaur]; } } } /* This code example produces the following output: Capacity: 3 Brachiosaurus Amargasaurus Mamenchisaurus AddRange[dinosaurs] Brachiosaurus Amargasaurus Mamenchisaurus Brachiosaurus Amargasaurus Mamenchisaurus RemoveRange[2, 2] Brachiosaurus Amargasaurus Amargasaurus Mamenchisaurus InsertRange[3, input] Brachiosaurus Amargasaurus Amargasaurus Tyrannosaurus Deinonychus Velociraptor Mamenchisaurus output = dinosaurs.GetRange[2, 3].ToArray[] Amargasaurus Tyrannosaurus Deinonychus */ Imports System.Collections.Generic Public Class Example Public Shared Sub Main[] Dim input[] As String = { "Brachiosaurus", _ "Amargasaurus", _ "Mamenchisaurus" } Dim dinosaurs As New List[Of String][input] Console.WriteLine[vbLf & "Capacity: {0}", dinosaurs.Capacity] Console.WriteLine[] For Each dinosaur As String In dinosaurs Console.WriteLine[dinosaur] Next Console.WriteLine[vbLf & "AddRange[dinosaurs]"] dinosaurs.AddRange[dinosaurs] Console.WriteLine[] For Each dinosaur As String In dinosaurs Console.WriteLine[dinosaur] Next Console.WriteLine[vbLf & "RemoveRange[2, 2]"] dinosaurs.RemoveRange[2, 2] Console.WriteLine[] For Each dinosaur As String In dinosaurs Console.WriteLine[dinosaur] Next input = New String[] { "Tyrannosaurus", _ "Deinonychus", _ "Velociraptor" } Console.WriteLine[vbLf & "InsertRange[3, input]"] dinosaurs.InsertRange[3, input] Console.WriteLine[] For Each dinosaur As String In dinosaurs Console.WriteLine[dinosaur] Next Console.WriteLine[vbLf & "output = dinosaurs.GetRange[2, 3].ToArray"] Dim output[] As String = dinosaurs.GetRange[2, 3].ToArray[] Console.WriteLine[] For Each dinosaur As String In output Console.WriteLine[dinosaur] Next End Sub End Class ' This code example produces the following output: ' 'Capacity: 3 ' 'Brachiosaurus 'Amargasaurus 'Mamenchisaurus ' 'AddRange[dinosaurs] ' 'Brachiosaurus 'Amargasaurus 'Mamenchisaurus 'Brachiosaurus 'Amargasaurus 'Mamenchisaurus ' 'RemoveRange[2, 2] ' 'Brachiosaurus 'Amargasaurus 'Amargasaurus 'Mamenchisaurus ' 'InsertRange[3, input] ' 'Brachiosaurus 'Amargasaurus 'Amargasaurus 'Tyrannosaurus 'Deinonychus 'Velociraptor 'Mamenchisaurus ' 'output = dinosaurs.GetRange[2, 3].ToArray ' 'Amargasaurus 'Tyrannosaurus 'Deinonychus

Remarks

The elements are copied onto the List in the same order they are read by the enumerator of the collection.

This constructor is an O[n] operation, where n is the number of elements in collection.

See also

• IEnumerable
• Capacity

List[Int32]

public: List[int capacity]; public List [int capacity]; new System.Collections.Generic.List Public Sub New [capacity As Integer]

Parameters

Exceptions

Examples

The following example demonstrates the List[Int32] constructor. A List of strings with a capacity of 4 is created, because the ultimate size of the list is known to be exactly 4. The list is populated with four strings, and a read-only copy is created by using the AsReadOnly method.

using namespace System; using namespace System::Collections::Generic; void main[] { List^ dinosaurs = gcnew List[4]; Console::WriteLine["\nCapacity: {0}", dinosaurs->Capacity]; dinosaurs->Add["Tyrannosaurus"]; dinosaurs->Add["Amargasaurus"]; dinosaurs->Add["Mamenchisaurus"]; dinosaurs->Add["Deinonychus"]; Console::WriteLine[]; for each[String^ dinosaur in dinosaurs] { Console::WriteLine[dinosaur]; } Console::WriteLine["\nIList^ roDinosaurs = dinosaurs->AsReadOnly[]"]; IList^ roDinosaurs = dinosaurs->AsReadOnly[]; Console::WriteLine["\nElements in the read-only IList:"]; for each[String^ dinosaur in roDinosaurs] { Console::WriteLine[dinosaur]; } Console::WriteLine["\ndinosaurs[2] = \"Coelophysis\""]; dinosaurs[2] = "Coelophysis"; Console::WriteLine["\nElements in the read-only IList:"]; for each[String^ dinosaur in roDinosaurs] { Console::WriteLine[dinosaur]; } } /* This code example produces the following output: Capacity: 4 Tyrannosaurus Amargasaurus Mamenchisaurus Deinonychus IList^ roDinosaurs = dinosaurs->AsReadOnly[] Elements in the read-only IList: Tyrannosaurus Amargasaurus Mamenchisaurus Deinonychus dinosaurs[2] = "Coelophysis" Elements in the read-only IList: Tyrannosaurus Amargasaurus Coelophysis Deinonychus */ using System; using System.Collections.Generic; public class Example { public static void Main[] { List dinosaurs = new List[4]; Console.WriteLine["\nCapacity: {0}", dinosaurs.Capacity]; dinosaurs.Add["Tyrannosaurus"]; dinosaurs.Add["Amargasaurus"]; dinosaurs.Add["Mamenchisaurus"]; dinosaurs.Add["Deinonychus"]; Console.WriteLine[]; foreach[string s in dinosaurs] { Console.WriteLine[s]; } Console.WriteLine["\nIList roDinosaurs = dinosaurs.AsReadOnly[]"]; IList roDinosaurs = dinosaurs.AsReadOnly[]; Console.WriteLine["\nElements in the read-only IList:"]; foreach[string dinosaur in roDinosaurs] { Console.WriteLine[dinosaur]; } Console.WriteLine["\ndinosaurs[2] = \"Coelophysis\""]; dinosaurs[2] = "Coelophysis"; Console.WriteLine["\nElements in the read-only IList:"]; foreach[string dinosaur in roDinosaurs] { Console.WriteLine[dinosaur]; } } } /* This code example produces the following output: Capacity: 4 Tyrannosaurus Amargasaurus Mamenchisaurus Deinonychus IList roDinosaurs = dinosaurs.AsReadOnly[] Elements in the read-only IList: Tyrannosaurus Amargasaurus Mamenchisaurus Deinonychus dinosaurs[2] = "Coelophysis" Elements in the read-only IList: Tyrannosaurus Amargasaurus Coelophysis Deinonychus */ Imports System.Collections.Generic Public Class Example Public Shared Sub Main[] Dim dinosaurs As New List[Of String][4] Console.WriteLine[vbLf & "Capacity: {0}", dinosaurs.Capacity] dinosaurs.Add["Tyrannosaurus"] dinosaurs.Add["Amargasaurus"] dinosaurs.Add["Mamenchisaurus"] dinosaurs.Add["Deinonychus"] Console.WriteLine[] For Each dinosaur As String In dinosaurs Console.WriteLine[dinosaur] Next Console.WriteLine[vbLf & _ "Dim roDinosaurs As IList[Of String] = dinosaurs.AsReadOnly"] Dim roDinosaurs As IList[Of String] = dinosaurs.AsReadOnly Console.WriteLine[vbLf & "Elements in the read-only IList:"] For Each dinosaur As String In roDinosaurs Console.WriteLine[dinosaur] Next Console.WriteLine[vbLf & "dinosaurs[2] = ""Coelophysis"""] dinosaurs[2] = "Coelophysis" Console.WriteLine[vbLf & "Elements in the read-only IList:"] For Each dinosaur As String In roDinosaurs Console.WriteLine[dinosaur] Next End Sub End Class ' This code example produces the following output: ' 'Capacity: 4 ' 'Tyrannosaurus 'Amargasaurus 'Mamenchisaurus 'Deinonychus ' 'Dim roDinosaurs As IList[Of String] = dinosaurs.AsReadOnly ' 'Elements in the read-only IList: 'Tyrannosaurus 'Amargasaurus 'Mamenchisaurus 'Deinonychus ' 'dinosaurs[2] = "Coelophysis" ' 'Elements in the read-only IList: 'Tyrannosaurus 'Amargasaurus 'Coelophysis 'Deinonychus

Remarks

The capacity of a List is the number of elements that the List can hold. As elements are added to a List, the capacity is automatically increased as required by reallocating the internal array.

If the size of the collection can be estimated, specifying the initial capacity eliminates the need to perform a number of resizing operations while adding elements to the List.

The capacity can be decreased by calling the TrimExcess method or by setting the Capacity property explicitly. Decreasing the capacity reallocates memory and copies all the elements in the List.

This constructor is an O[1] operation.

See also

• Capacity