Using C# LINQ - A Practical Overview



The C# programming language is quite popular with developers, in large part because of its many powerful and intuitive language features. One of these impressive (and fun, in a nerdy way) features is LINQ.

What is LINQ?

LINQ is a libary used to execute queries directly in C# syntax against many types of data. It is implemented as a set of extension methods on the IEnumerable<T> interface.

NOTE: More informaiton on extension methods and IEnumerable<T> can be found in the LINQ Background Topics course.


The acronym LINQ stands for Language Integrated Query. LINQ syntax is roughly derived from SQL. New C# developers often misinterpret this to mean that LINQ is a database access API. Although it is true that LINQ was conceived as a way to access data in a database from code, that is not the extent of its utility.

The LINQ paradigm

The LINQ paradigm describes a method for programmatically accessing and manipulating any data, independent of the source. There are many implementations of LINQ, each written to access a different kind of data source. Some of the common ones include: LINQ to SQL, LINQ to XML, and LINQ to Objects.

LINQ to Objects

Although this course works with LINQ to Objects, many of the concepts learned here can be applied to other LINQ implementations. LINQ to Objects provides access to data stored in C# collections such as lists and arrays.

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