C# | Getting a subset of the elements from the source ArrayList (original) (raw)

Last Updated : 01 Feb, 2019

ArrayList.GetRange(Int32, Int32) Method is used to get an ArrayList which will represent a subset of the elements in the source ArrayList.Syntax:

public virtual System.Collections.ArrayList GetRange (int index, int count);

Parameters:

index: It is of Int32 type and represents the zero-based ArrayList index at which the range starts.count: It is of Int32 type and represents the number of elements in the range.

Return Value: This method returns an ArrayList which represents a subset of the elements in the source ArrayList.Exceptions:

• ArgumentOutOfRangeException: If the value of the index is less than zero, or if the value of count is less than zero.
• ArgumentException: If the value of an index and count does not denote a valid range of elements in the ArrayList.

Below programs illustrate the above-discussed method:Example 1:

CSharp `

// C# program to illustrate the // concept of GetRange() Method using System; using System.Collections;

class GFG {

// Main method
public static void Main()
{

    // Creates and initializes
    // a new ArrayList.
    ArrayList myarraylist = new ArrayList();
    myarraylist.Add("Welcome");
    myarraylist.Add("to");
    myarraylist.Add("Geeks");
    myarraylist.Add("for");
    myarraylist.Add("Geeks");
    myarraylist.Add("portal");

    // Creates and initializes queue
    Queue mynewList = new Queue();
    mynewList.Enqueue("This");
    mynewList.Enqueue("is");
    mynewList.Enqueue("C#");
    mynewList.Enqueue("tutorial");

    // Displays the values of six 
    // elements starting at index 0.
    ArrayList newarraylist = myarraylist.GetRange(0, 6);
    Console.WriteLine("Elements are:");
    Displaydata(newarraylist, '\n');

    // Replaces the values of six elements 
    // starting at index 1 with the values
    // in the queue.
    myarraylist.SetRange(2, mynewList);

    // Displays the values of six 
    // elements starting at index 0.
    newarraylist = myarraylist.GetRange(0, 6);
    Console.WriteLine("\nNow elements are:");
    Displaydata(newarraylist, '\n');
}

public static void Displaydata(IEnumerable myvalueList,
                                      char mySeparator)
{
    foreach(Object obj in myvalueList)
        Console.Write("{0}{1}", mySeparator, obj);
    Console.WriteLine();
}

}

`

Output:

Elements are:

Welcome to Geeks for Geeks portal

Now elements are:

Welcome to This is C# tutorial

Example 2:

CSharp `

// C# program to illustrate the // concept of GetRange() Method using System; using System.Collections;

class GFG {

// Main method
public static void Main()
{

    // Creates and initializes a new ArrayList.
    ArrayList myarraylist = new ArrayList();
    myarraylist.Add("Welcome");
    myarraylist.Add("to");
    myarraylist.Add("Geeks");
    myarraylist.Add("for");
    myarraylist.Add("Geeks");
    myarraylist.Add("portal");

    // Creates and initializes queue
    Queue mynewList = new Queue();
    mynewList.Enqueue("This");
    mynewList.Enqueue("is");
    mynewList.Enqueue("C#");
    mynewList.Enqueue("tutorial");

    // Displays the values of six elements
    ArrayList newarraylist = myarraylist.GetRange(-1, 6);
    Console.WriteLine("Elements are:");
    Displaydata(newarraylist, '\n');

    // Replaces the values of six elements 
    // starting at index 1 with the 
    // values in the queue.
    myarraylist.SetRange(2, mynewList);

    // Displays the values of six 
    // elements starting at index 0.
    newarraylist = myarraylist.GetRange(0, 6);
    Console.WriteLine("Now elements are:");
    Displaydata(newarraylist, '\n');
}

public static void Displaydata(IEnumerable myvalueList, 
                                      char mySeparator)
{
    foreach(Object obj in myvalueList)
        Console.Write("{0}{1}", mySeparator, obj);
    Console.WriteLine();
}

}

`

Runtime Error:

Unhandled Exception: System.ArgumentOutOfRangeException: Non-negative number required. Parameter name: index

Reference:

• https://docs.microsoft.com/en-us/dotnet/api/system.collections.arraylist.getrange?view=netframework-4.7.2#System_Collections_ArrayList_GetRange_System_Int32_System_Int32_