Fundamentals of Python - functional programming

Preface ： This article is abstract , First, sort it out and record it , Work slowly to understand .

1、 Functional programming definition

In short ," Functional programming " It's a kind of " Programming paradigm "（programming paradigm）, The methodology of how to write a program .
Common programming paradigms are ： Process oriented programming , object-oriented programming , Functional programming .

Python It's a multi paradigm programming language , This includes object-oriented programming , Functional programming .

2、 Functional programming features

• The function is " First class citizens "
  • Functions can be the same as variables , It can be assigned to other variables , It can also be used as a parameter , Pass in a function , Or as the return value of another function .
• Just use expressions , No statement ：
  • An expression is a simple operation , There is always a return value .
  • A statement is to perform an operation , no return value .
  • in other words , Every step in functional programming is a simple operation , And they all have return values .
• No side effect
  • It will not produce results other than operations .
  • The same input always gets the same data .
• Immutability
  • Do not modify variables , Returns a new value .
• Reference transparent
  • The operation of the function does not depend on external variables , It only depends on the input parameters .

3、 The application of functional programming

Higher order function

Partial function

Closure

recursive

The inertia calculation

currying

4、 The advantages of functional programming

The code is concise , Fast development

Close to natural language , Easy to understand

Easier code management

Easy to " Concurrent programming "

Hot code upgrades

5、 The disadvantages of functional programming

The runtime is heavily consumed in CPU And storage resources , Poor performance

reference：

Functional programming _ Baidu Encyclopedia

Programming paradigm — The idea behind the programming language - zhoulujun - Blog Garden