Hands-On Reactive Programming with Python

Higher-order functions

The last concept that is important to know when starting with functional programming is higher-order functions. A higher-order function is a function that accepts a function as an input parameter and/or returns a function as an output parameter. There are different reasons to use higher-order functions:

• By taking functions as input, higher-order functions allow you to implement generic behavior on different types of actions. This allows you to factorize some code.

• Returning a function as an output allows you to capture the values of input arguments, thanks to closures, and return a function that operates on a fixed set of parameters.

Both of these situations are covered in the example of the Closures section: