4.4.1. Functional programming in Python

4.4.1.1. Abstraction for behaviors

Object-oriented programming (OOP) is the abstraction for things that have noun attribute. Just like biological classification, scientists use the context Domain, Kingdom, Phylum, Class, Order, Family, and Genus to describe creatures. It is scientifically rigorous, comprehensive, but not such flexible to deal with open set. (for example to describe a totally new specie which can not been interpreted in this system indeed).

Functional programming (FP) is the abstraction for things that have verb attribute. We describe the data without modification raw; we define the process steps for data as preprocessing; we called the behaviors of extracting informative things from data feature engineering; we train to find the pattern possibly underlying the data. No matter what investigation in what field we are struggling, we repeat those behaviors step by step, always.

4.4.1.2. Using functions

Like many other programming languages, python is also supports multi-paradigm well. The function can be used as value to pass in, the modified function can be return as a value as well, after which the currying occurs.

Note

The term function currying refers the changes of calling for function with form of f1(a, b, c), into the form as f2(a)(b)(c). In modern programming, this architecture is helpful to decoupling our operation logic on data. In the last form, f2(a) return a function that the behavior a is determined; then f2(a)(b) return the behavior b is determined as well; assume the c is the data, it is clear that data c can be processed, if and only if the pre-processes a and b are pre defined.

For building the function with high reusability, here shows some advice:

  • make arguments concise when parameterization

  • variable-length arguments will make function easy to be extended

  • design for call back in where calculation method might vary

  • for one-time manipulating, use lambda

Authors:

Chen Zhang

Version:

0.0.5

Created on:

Jun 16, 2023