Different people have different definitions for functions, for instance, computer scientists and programmers might call it a data structure mechanism that takes and input and performs operations, and (sometimes) returns a result.
Mathematicians might call functions as a way to model behavior of an input parameter. (Calculus to Topology). Physicists use functions to emulate the changing states of real world objects.
In essence all these are are talking about the same thing. Functions are quintessentially, structures that take in an Input and return an output based on given operands.
This Swift Playground is about teaching Hashing Functions to students. I take through Hash Functions from 2 vantage points. They are File Comparisons and Hashed Lookups. These are the 2 ways that Hashing Functions are used.
For more info on how to use this Playground here, please check here :https://youtu.be/qtJhLRvTBi8