You may have heard of Active Patterns before – typically in conjunction with the words ‘awesome’ or ‘amazing’. Active Patterns are one of the more unique language features in F# and once you get a good feel for them one of the most powerful. This post will demonstrate Active Patterns from single-case and multi-case to partial and parameterized. If it’s called an Active Pattern, you’ll see an example in this post. So let’s get started.