What are the applications of LINQ in C#?

In C#, LINQ (Language Integrated Query) is widely used for querying and manipulating various data sources, including but not limited to:

1. Query set: With LINQ, it is easy to filter, sort, and group collections.
2. Database querying with LINQ is made possible in C# through ORM frameworks like LINQ to SQL and Entity Framework.
3. XML querying: LINQ to XML enables easy querying and manipulation of XML documents in C#.
4. Querying Objects: LINQ can be used to query custom collections of objects, making it easy to filter, sort, and manipulate objects using LINQ.
5. Parallel querying: Parallel LINQ (PLINQ) allows for parallel querying, improving query efficiency.
6. LINQ to Objects allows for querying of any object that implements the IEnumerable interface, not just collections.
7. Data transformation: LINQ can also be used for data transformation, projection, and other operations to manipulate and process data.

In general, LINQ offers a unified querying syntax and API, simplifying the process of data querying and manipulation, thus increasing code readability and maintainability.