Learning---Anonymous functions and closures in Python learning

1.1. Anonymous Functions

Anonymous　naming rules for name functions : identified by the LAMDBA keyword, the left side of the colon (:) indicates the parameter (a, b) that the function receives, and the right side of the colon (:) represents the function's return value (A+B). Because LAMDBA does not need to be named when it is created, it is called an anonymous function

Add = lambda A, b:a * bprint (Add (2, 3))    #  6

1.2. functional programming and imperative programming

Our common programming paradigm is command-programmed (imperative programming), functional Programming

Common object-oriented programming is also a kind of imperative programming.

Imperative Programming is an abstraction for computer hardware , with variables (corresponding to storage units), assignment Statements (fetch, store instructions), expressions (memory references and arithmetic operations), and Control statement (jump instruction), in a word, the imperative program is a Von Neumann sequence of instructions .
Functional Programming is a mathematical-oriented abstraction that describes computation as an expression evaluation , in a word, a functional program is an expression .

Functional programming concerns the mapping of data, imperative programming cares about the steps to solve the problem

1.3. Closed Package

definition: If a reference is made to a variable in an external scope (but not at the global scope) in an intrinsic function, then the intrinsic function is considered a closure (closure).

simply speaking , it's closures = function blocks (intrinsic functions) + (external) environment variables when defining intrinsic functions

# DEF outer (x):  # When this x variable is passed in as a parameter, it is equivalent to the external variable of the intrinsic Function Def outer ():    x =    def inner ():        print (x)    return inner# yy = outer (+) # yy () The result of the execution is 100, the same reason XX = outer ()   # outer () has performed the completion of XX ()           #  Why outer has been executed, But inner () can also fetch the x=10 value?               # Closures (closure)! The inner of return in outer is a closure function with an environment variable of x. Outer () ()      # 19# inner ()      #  name ' inner ' is not defined  scope is local# print (x)     #  name ' x ' are not Defined   Scope Local

Learning---Anonymous functions and closures in Python learning