Programmer Group

Catalog object-oriented programming __str__( ) __repr__( ) _ iter_() and _next_() __getitem__( ) __setitem__( ) __delitem__( ) __getattr__( ) __call__( ) object-oriented programming Previously, it has been introduced that _xxx_ is a special variable or function, such as _init_ and _slots_. This section will introduce more sp ...

1: Ordinary ornaments Concept: without changing the internal code of the original function, a function is automatically executed before and after the function is executed, adding a function to an existing object Format for Ordinary Decorators def Outer layer function(parameter) def Inner Function(*args,**kwargs) #Before f ...

1. Refactoring code to improve readability and flexibility 1. Improving code readability New features of Java 8 can also help improve code readability: With Java 8, you can reduce verbose code and make it easier to understand. With method references and Stream API s, your code becomes more intuitive Here we will introduce three simple refacto ...

note address a='123' b='123' print(a==b) print(a is b)##True, the id of the immutable type is the same, the address is the same print(id(a))#identical print(id(b))#identical a=3 b=a b=6 print(a) a=[1,2,3] b=[1,2,3] print(a==b)#true print(a is b)##Different IDs and addresses for false variable types print(id(a))#Different ID s ...

I. Preface In daily development, we often encounter the need to know the number of objects at runtime. This situation can not use arrays, because arrays are a fixed number, we will use collections at this time, because collections can store an indefinite number of objects. Collection classes are particularly useful tool classes. They can stor ...

Let's talk about iterators, which are a very useful tool and are widely used throughout the EOS code base. If you come from a JavaScript background, you may already be familiar with iterators, just as they are used for loops. The key concept of iterators is to provide a better way to traverse item sets. The additional benefit is that you can im ...

NumPy is a Python library for scientific computing in Python programming. In this tutorial, you will learn how to add, delete, sort and manipulate elements in NumPy arrays in a variety of ways. NumPy provides a multidimensional array object and other derived arrays, such as mask arrays and mask multidimensional arrays. Why use NumPy NumPy provi ...

JAVA8 Actual Warfare Introduction to this fragment:   Java 8 Stream provides us with a convenient grouping collector by which we can easily group according to the value of an attribute of each element of an object set. After grouping common usage, the entire set of objects is divided into groups of the number of values of t ...

Catalog 1. variable constant 2. User interaction and annotations Program interaction Notes Character string Boolean type Format output operator while cycle @ (Development Foundation) 1. variable Variables are used to store information to ...

data structure What is a data structure? Simply put, data structure is to design how data is organized and stored in a computer. Lists, collections and dictionaries are all data structures. N.Wirth: "Program = Data Structure + Algorithms"   list List: In other programming languages, called "arrays", is a basic data structur ...