C# | Sets the capacity to the actual number of elements in the ArrayList
ArrayList.TrimToSize Method is used to set the capacity to the actual number of elements in the ArrayList. It can be used to minimize a collection’s memory overhead if no new elements will be added to the collection. Note: This method is an O(n) operation, where n is Count. Syntax:
public virtual void TrimToSize ();
Exception: This method will give NotSupportedException if the ArrayList is read-only or has a fixed size. Below given are some examples to understand the implementation in a better way: Example 1:
CSharp
// C# program to illustrate the TrimToSize() Method using System; using System.Collections; class GFG { // Main method public static void Main() { // create and initialize new ArrayList ArrayList mylist = new ArrayList(); mylist.Add("Beginner"); mylist.Add("GFG"); mylist.Add("DSA"); mylist.Add("C#"); mylist.Add("Java"); mylist.Add("C++"); // Capacity of ArrayList before trimming Console.WriteLine("Before trimming the capacity is : {0}", mylist.Capacity); // trim the ArrayList mylist.TrimToSize(); // Capacity of ArrayList after trimming Console.WriteLine("After trimming the capacity is : {0}", mylist.Capacity); } } |
Output:
Before trimming the capacity is: 8 After trimming the capacity is: 6
Example 2:
CSharp
// C# program to illustrate the TrimToSize() Method using System; using System.Collections; class GFG { // Main Method public static void Main() { // Creating and initializing a new ArrayList. ArrayList mylist = new ArrayList(); mylist.Add("C# "); mylist.Add("Java "); mylist.Add("C++ "); mylist.Add("DSA "); mylist.Add("Python "); mylist.Add("Web"); // Displaying the count, capacity // and values of the ArrayList. Console.WriteLine("Before Using TrimToSize Method:"); Console.WriteLine("Count: {0}", mylist.Count); Console.WriteLine("Capacity: {0}", mylist.Capacity); Console.Write("Values are: "); Display(mylist); Console.WriteLine(); // Trim the ArrayList. mylist.TrimToSize(); // Displaying the count, capacity // and values of the ArrayList. Console.WriteLine("After Using TrimToSize Method:"); Console.WriteLine("Count: {0}", mylist.Count); Console.WriteLine("Capacity: {0}", mylist.Capacity); Console.Write("Values are: "); Display(mylist); // Clear the ArrayList. mylist.Clear(); Console.WriteLine(); // Displaying the count, capacity // and values of the ArrayList. Console.WriteLine("After Using Clear Method:"); Console.WriteLine("Count: {0}", mylist.Count); Console.WriteLine("Capacity: {0}", mylist.Capacity); Console.Write("Values are: "); Display(mylist); // again trim the ArrayList mylist.TrimToSize(); Console.WriteLine(); // Displaying the count, capacity // and values of the ArrayList. Console.WriteLine("After Again Using TrimToSize Method:"); Console.WriteLine("Count: {0}", mylist.Count); Console.WriteLine("Capacity: {0}", mylist.Capacity); Console.Write("Values are: "); Display(mylist); } // to display the values of ArrayList public static void Display(IEnumerable ienum) { foreach (Object ob in ienum) Console.Write("{0}", ob); Console.WriteLine(); } } |
Output:
Before Using TrimToSize Method: Count: 6 Capacity: 8 Values are: C# Java C++ DSA Python Web After Using TrimToSize Method: Count: 6 Capacity: 6 Values are: C# Java C++ DSA Python Web After Using Clear Method: Count: 0 Capacity: 6 Values are: After Again Using TrimToSize Method: Count: 0 Capacity: 4 Values are:
Reference:
- https://docs.microsoft.com/en-us/dotnet/api/system.collections.arraylist.trimtosize?view=netframework-4.7.2
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