Functional Programming in Data Engineering with Python — Part 1

What is functional programming?

• 함수프로그래밍은 함수를 사용하여 bug-resistant program그리고 응용프로그램을 구축하는데 사용되는 declartive type of programming

• 작업수행방법( imperative programming)에 대한 단게를 지정하는 대신에 side effect를 완화를 위한 순수기능과 immutable data structure사용을 강조하는 computing paradigm

Function 특징

• An input (parameter for another function)

• An output (result from another function) Also, functions:

• are treated as first-class citizens (first-class functions)
• can be passed into other functions as arguments or returned from other functions (higher-order functions)`
• can be connected with other functions to form new ones (function composition)`
• should be designed to work with other functions (reusability)`

Core principles of functional programming

1. monoids
2. immutability
3. recursion
4. function composition
5. dependency injection
6. currying
7. referential transparency
8. lazy evaluations

1. monoids

• closure : input/output type은 같다
• identity : empty 또는 string을 입력값을 넣으면 결과가 그대로 유지
• associativity : 원하는대로 값을 순서대로 지정할 수 있지만, 여전히 동일한 답을 얻을 수 있음

2. Immutability

• object는 immutable
• functional programming에서 object가 생성되거나 초기화되면 상태를 변경할 수 없는 경우

  Mutable data structure

• lists
• dictionaries
• sets

Immutable data structure

• strings
• tuples
• frozensets

참고

• ![medium]https://blog.det.life/functional-programming-in-data-engineering-with-python-part-1-c2c4f677f749)