Gain insights into Haskell's functional programming by learning to write pure functions, use pattern matching, recursion, and Lists, define data types, and execute IO operations.

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Functional programming is a problem-solving paradigm that differs drastically from the imperative programming style of languages like C++ or Java. While functional programming principles have invaded most modern programming languages to some degree, there is no language that embraces this paradigm quite as Haskell does. As a result, Haskell code can reach a level of expressiveness, safety, and elegance that is difficult to achieve in other programming languages.

This course will introduce you to the core concepts of functional programming in Haskell. You will learn how to write pure functions using techniques such as pattern matching and recursion, and how to work with Haskell's powerful List data type. You will understand the basics of Haskell's powerful type system and define your own data types. Finally, you’ll learn how to perform IO operations the Haskell way. By the end of this course, you’ll have a new paradigm to add under your belt and you can start using functional programming in your own projects.

Learn Functional Programming in Haskell

In the final lesson on lists, we take a look at another powerful syntactic element to build complex lists: the **list comprehension** syntax.

# List comprehensions by example

List comprehensions are a concept inspired by **set definitions** in mathematical notation.  In mathematics, the definition
$$ \{ x^2 \ |\ x \in \mathbb{N}, x \text{ is even} \}$$
defines the set of even squares. It is advised to start reading such a set definition from the right of the separating pipe symbol `|`. 
1. The elements $x$ are drawn from the set of natural numbers $\mathbb{N}$.
2. Only the even $x$ are kept.
3. Finally (to the left of the pipe `|`), the set consists of the squares of these even $x$.

Similarly, we can define a list of the even squares in Haskell by using the closely related list comprehension syntax. 


Learn how to build lists using list comprehensions.

Introduction

First Steps with Haskell

Techniques for Writing Functions

Working with Lists

Creating Data Types

Input and Output

Conclusion

Appendix

List Comprehension

List comprehensions by example