Dictionary

Description

Dictionary collection contains a group of elements of key/value pairs.

Dictionary<TKey, TValue> referenceVariable = new Dictionary<TKey, TValue>();

• Full Path: System.Collections.Generic.Dictionary.
• The Dictionary class is a generic class; so you need to specify the data type of the key and the data type of the value while creating the object.
• You can set/get the value based on the key.
• The key can't be null or duplicate.
• It is dynamically sized. You can add, remove elements (key/value pairs) at any time.
• The key can't be null or duplicate, but values can be null or duplicate.
• It is not index-based. You need to access elements by using key.
• It is not sorted by default. The elements are stored in the same order, exactly how they are initialized.

Example:

Dictionary<int, string> employees = new Dictionary<int, string>()
{
    { 101, "Scott" },
    { 102, "Smith" },
    { 103, "Allen" }
};

foreach (KeyValuePair<int, string> item in employees) {
    Console.WriteLine(item.Key + ", " + item.Value);
}

Features

Overview