Scala and Spark for Big Data Analytics

Pure functions

One of the most important principles of functional programming is pure functions. So what are pure functions and why do we care about them? In this section, we will address this important feature of functional programming. One of the best practices of functional programming is to implement your programs such that the core of your program/application is made from pure functions and all the I/O functions or side effects such as network overhead and exceptions are in an exposed external layer.

So what are the benefits of pure functions? Pure functions are normally smaller than normal functions (although it depends on other factors such as programming language) and even easier to interpret and understand for the human brain because ...