What are the functions of a C# dictionary?

In C#, a Dictionary is a collection of key-value pairs that serves the following purposes:

1. Storing and retrieving data: Dictionaries can be used to store and retrieve large amounts of data. Each key-value pair has a unique key and corresponding value, allowing you to look up and access the value by its key.
2. Quick search: Dictionary uses a hashtable to achieve high efficiency in search operations. When searching for a value by key, it does not need to traverse the entire collection, but instead finds the corresponding position directly based on the key’s hash value.
3. Deduplication: The keys in a Dictionary are unique and can be used for deduplication. When you need to store a set of elements and ensure their uniqueness, you can use a Dictionary for deduplication.
4. Mapping Relationship: A dictionary can be used to establish a mapping relationship between two sets. By using the elements of one set as keys and the elements of another set as values, a correspondence between the two sets can be established.

In conclusion, the Dictionary in C# is a commonly used data structure that can be utilized for storing and retrieving data, fast searching, removing duplicates, and establishing mapping relationships in various scenarios.