C# | Remove all elements from a SortedList

Last Updated : 01 Feb, 2019

SortedList class is a collection of (key, value) pairs which are sorted according to keys. Those pairs can be accessible by key and as well as by index(zero-based indexing). This comes under System.Collections namespace. SortedList.Clear method is used to remove all the elements from a SortedList object. Properties:

A SortedList element can be accessed by its key or by its index.
A SortedList object internally maintains two arrays to store the elements of the list, i.e, one array for the keys and another array for the associated values.
A key cannot be null, but a value can be.
The capacity of a SortedList object is the number of elements the SortedList can hold.
A SortedList does not allow duplicate keys.
Operations on a SortedList object tend to be slower than operations on a Hashtable object because of the sorting.
Elements in this collection can be accessed using an integer index. Indexes in this collection are zero-based.

Syntax :

  public virtual void Clear ();

Exceptions:

NotSupportedException : If the SortedList object is read-only or has a fixed size.

Example:

CSHARP

// C# code to remove all // elements from a SortedList using System; using System.Collections;  class GFG {      // Driver code     public static void Main()     {          // Creating an SortedList         SortedList mySortedList = new SortedList();          // Adding elements to SortedList         mySortedList.Add("1", "1st");         mySortedList.Add("2", "2nd");         mySortedList.Add("3", "3rd");         mySortedList.Add("4", "4th");         mySortedList.Add("5", "5th");         mySortedList.Add("6", "6th");         mySortedList.Add("7", "7th");          // Displaying number of elements         Console.WriteLine("Number of elements in SortedList is : "                                              + mySortedList.Count);          // Displaying capacity         Console.WriteLine("capacity of SortedList is : "                                 + mySortedList.Capacity);          // Removing all elements from SortedList         mySortedList.Clear();          // Displaying number of elements         Console.WriteLine("Number of elements in SortedList is : "                                             + mySortedList.Count);          // Displaying capacity         Console.WriteLine("capacity of SortedList is : "                                 + mySortedList.Capacity);     } }

Output:

  Number of elements in SortedList is : 7  capacity of SortedList is : 16  Number of elements in SortedList is : 0  capacity of SortedList is : 16

Note:

This method is an O(n) operation, where n is Count.
Count is set to zero and references to other objects from elements of the collection are also released.
Capacity remains unchanged. To reset the capacity of the SortedList object, call TrimToSize or set the Capacity property directly.
Trimming an empty SortedList sets the capacity of the SortedList to the default capacity.

Reference: