Python iterators, generators and adorners

1 "The principle and use of iterators:
1> principle:
Iterators are a way to access the elements of a collection, and the iterator object is accessed from the first element of the collection until all the elements have been accessed, and the iterator can only move forward without going backwards, but that's fine, and there's little to go backwards in the iteration, and one of the great advantages of iterators is that they don't require preparation for the entire iteration An iterator that computes an element only when it iterates over an element, before or after which the element may not exist or is destroyed; This feature makes it particularly useful for traversing large or infinite collections, such as several G files;
Characteristics:
(1) The visitor does not need the structure within the relational iterator, but only needs to go through the next () method to fetch the content;
(2) Can not randomly access a value in the collection, can only be accessed from beginning to end;
(3) can not return to half of the visit;
(4) Easy to cycle relatively large data collection, save memory;
2> generates an iterator: 3 using __next__ () to view;

2 "Generator (generator):
Definition: When a function call returns an iterator, the function is called the generator, and if the function contains the yield syntax, the function becomes the generator;
The main role of yield:
You can break the function and save the interrupt state, the code can continue to execute after the break, and after a period of time it can be recalled again, starting from the next sentence of the last yield;
Generation of the 1> generator:

2> uses yield to implement asynchronous concurrency effects in multiple threads:

2 "Decorator: Extend new functions to the functions that have been realized;
1> a similar adorner without parameters;

A similar adorner with 2> parameters;

3> Decorator:

4> implements a complex adorner with parameters: a function is decorated with multiple adorners;

Process Analysis:

Python iterators, generators and adorners