How to Print Hashtable in C#

In C#, a Hashtable is a collection that stores key-value pairs. Once populated, you can print the contents of the Hashtable to verify its data or provide useful output. This article will guide you through the process of printing a Hashtable in C# using different techniques and best practices.

Printing Methods

Iterating Through Hashtable with Foreach

The Hashtable class implements the IEnumerable interface, allowing iteration through each key-value pair using a foreach loop. Here’s how you can print the entire Hashtable:

using System;
using System.Collections;

public class HashtablePrintExample
{
    public static void Main()
    {
        // Create and populate a hashtable
        Hashtable studentScores = new Hashtable
        {
            { "Alice", 95 },
            { "Bob", 88 },
            { "Charlie", 78 },
            { "Diana", 85 }
        };

        // Print each key-value pair using a foreach loop
        Console.WriteLine("Student Scores:");
        foreach (DictionaryEntry entry in studentScores)
        {
            Console.WriteLine($"{entry.Key}: {entry.Value}");
        }
    }
}

Accessing Values by Key

You can also print individual values by accessing them directly via their keys:

using System; using System.Collections; public class HashtableSinglePrintExample {    public static void Main()    {        // Create and populate a hashtable        Hashtable countries = new Hashtable        {            { "USA", "Washington, D.C." },            { "UK", "London" },            { "Japan", "Tokyo" },            { "India", "New Delhi" }        };        // Print specific values by key        Console.WriteLine($"Capital of USA: {countries["USA"]}");        Console.WriteLine($"Capital of Japan: {countries["Japan"]}");    } }

Formatting Output with String Methods

To make the printed output more readable, use string formatting methods:

using System;
using System.Collections;

public class HashtableFormattedPrintExample
{
    public static void Main()
    {
        // Create and populate a hashtable
        Hashtable products = new Hashtable
        {
            { "P001", "Laptop" },
            { "P002", "Smartphone" },
            { "P003", "Tablet" }
        };

        // Print the formatted output
        Console.WriteLine("Product List:");
        foreach (DictionaryEntry product in products)
        {
            Console.WriteLine($"Product ID: {product.Key}, Name: {product.Value}");
        }
    }
}

Best Practices for Printing Hashtable

Order Consistency: Be aware that Hashtable doesn't maintain order.
Null Handling: Handle null keys and values gracefully during printing.
String Interpolation: Use string interpolation or formatting for cleaner output.

Conclusion

Printing the contents of a Hashtable in C# is straightforward using loops or direct key access. Following best practices will help ensure clear and accurate output, making it easier to verify and share the collection's data.

how to print hashtable in c#