Unlocking the Power of Hashtables in C#
What is a Hashtable?
A Hashtable is a powerful data structure that stores key-value pairs, organized based on the hash code of each key. As a non-generic collection, it implements the ICollection interface, making it a versatile tool for developers.
Getting Started with Hashtables
To create a Hashtable in C#, you need to use the System.Collections namespace. Here’s a simple example to get you started:
csharp
Hashtable myTable = new Hashtable();
Mastering Basic Operations on Hashtables
Hashtables offer a range of operations that make them a valuable asset in your coding arsenal. Let’s dive into the most commonly used ones:
Adding Elements
C# provides the Add() method, which allows you to add elements to a Hashtable. For instance:
csharp
myTable.Add("Subject", "Math");
myTable.Add("Code", 139);
Note that keys must be unique and cannot be null, while values can be null or duplicate.
Accessing Elements
You can access elements inside a Hashtable using their keys. Here’s an example:
csharp
string employee = (string)myTable["Employee"];
int id = (int)myTable["Id"];
Iterating Through Hashtables
C# offers two ways to iterate through a Hashtable: using a foreach loop or by leveraging DictionaryEntry. Let’s explore both options:
csharp
foreach (DictionaryEntry entry in myTable)
{
Console.WriteLine("Key = {0}, Value = {1}", entry.Key, entry.Value);
}
Or:
csharp
foreach (object key in myTable.Keys)
{
Console.WriteLine("Key = {0}, Value = {1}", key, myTable[key]);
}
Changing Elements
You can modify the value of elements in a Hashtable as follows:
csharp
myTable["Address"] = "New Address";
Removing Elements
To remove elements from a Hashtable, use the Remove() method, specifying the key of the element you want to delete:
csharp
myTable.Remove("Id");
By mastering these basic operations, you’ll unlock the full potential of Hashtables in C# and take your coding skills to the next level.