List<T>.GetRange(Int32, Int32) Method
Definition
Important
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Creates a shallow copy of a range of elements in the source List<T>.
public:
System::Collections::Generic::List<T> ^ GetRange(int index, int count);public System.Collections.Generic.List<T> GetRange (int index, int count);member this.GetRange : int * int -> System.Collections.Generic.List<'T>Public Function GetRange (index As Integer, count As Integer) As List(Of T)Parameters
- count
- Int32
The number of elements in the range.
Returns
A shallow copy of a range of elements in the source List<T>.
Exceptions
index and count do not denote a valid range of elements in the List<T>.
Examples
The following example demonstrates the GetRange method and other methods of the List<T> class that act on ranges. At the end of the example, the GetRange method is used to get three items from the list, beginning with index location 2. The ToArray method is called on the resulting List<T>, creating an array of three elements. The elements of the array are displayed.
using namespace System;
using namespace System::Collections::Generic;
void main()
{
array<String^>^ input = { "Brachiosaurus",
"Amargasaurus",
"Mamenchisaurus" };
List<String^>^ dinosaurs =
gcnew List<String^>((IEnumerable<String^>^) 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<String^> { "Tyrannosaurus",
"Deinonychus",
"Velociraptor"};
Console::WriteLine("\nInsertRange(3, (IEnumerable<String^>^) input)");
dinosaurs->InsertRange(3, (IEnumerable<String^>^) input);
Console::WriteLine();
for each(String^ dinosaur in dinosaurs )
{
Console::WriteLine(dinosaur);
}
Console::WriteLine("\noutput = dinosaurs->GetRange(2, 3)->ToArray()");
array<String^>^ 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<String^>^) 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<string> dinosaurs = new List<string>(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
A shallow copy of a collection of reference types, or a subset of that collection, contains only the references to the elements of the collection. The objects themselves are not copied. The references in the new list point to the same objects as the references in the original list.
A shallow copy of a collection of value types, or a subset of that collection, contains the elements of the collection. However, if the elements of the collection contain references to other objects, those objects are not copied. The references in the elements of the new collection point to the same objects as the references in the elements of the original collection.
In contrast, a deep copy of a collection copies the elements and everything directly or indirectly referenced by the elements.
This method is an O(n) operation, where n is count.
