HashMap in C#
Minahil Noor
Dec 21, 2022
Mar 09, 2021
Csharp

This article will introduce a hashmap equivalent in C#.
Use the Dictionary
Collection as Hashmap Equivalent in C#
We will use the Dictionary
collection as hashmap equivalent in C#. It represents a collection of key-value pairs. The key-value pair means that every value has a key. The correct syntax to create a dictionary is as follows.
IDictionary<type, type> numberNames = new Dictionary<type, type>();
There are multiple methods to perform operations on the created dictionary such as Add()
, Clear()
, ContainsKey()
, ContainsValue()
, Equals()
, GetType()
, Remove()
, etc.
The program below shows how we can add elements to the dictionary.
using System;
using System.Collections.Generic;
public class Program {
public static void Main() {
IDictionary<int, string> flowerNames = new Dictionary<int, string>();
flowerNames.Add(1,"Rose");
flowerNames.Add(2,"Jasmine");
flowerNames.Add(3,"Lili");
foreach(KeyValuePair<int, string> kvp in flowerNames)
Console.WriteLine("Key: {0}, Value: {1}", kvp.Key, kvp.Value);
}
}
Output:
Key: 1, Value: Rose
Key: 2, Value: Jasmine
Key: 3, Value: Lili
There are some limitations to the Dictionary
collection. We cannot add null keys to it. If we do, then it will throw ArgumentNullException
.