understanding gfr

A deep understanding of this in the Javascript arrow function and a deep understanding of javascript First, let's take a look at the code. This is a Countdown class "Countdown" and Its instantiation process: function Countdown(seconds) { this._seconds = seconds;}Countdown.prototype._step = function() { console.log(this._seconds); if (this._seconds > 0) { this._seconds -= 1; } else { clearInterval(this._ti

A deep understanding of the operating principles of various methods in Python, and a deep understanding of python How does the method work in Python? A method is a function that exists as a class attribute. You can declare and access a function in the following way: >>> class Pizza(object):... def __init__(self, size):... self.size = size... def get_size(self):... return self.size...>>> Pizza.ge

Deep understanding of Vue conditional rendering and list rendering, deep understanding of vue I learned a lot about conditional rendering and list rendering in Vue. js over the past two days, and it is very important. So, add a little note today. Conditional Rendering V-if Use v-if in When using the v-if control element, we need to add it to this element. However, it is too troublesome to add multiple elem

A deep understanding of the principles of Vue one-way data streams and a deep understanding of vue data streams What is one-way data stream? One-way data streams can only modify the status in one direction. It is a simple example of unidirectional data streams: Simple diagram of one-way data stream A unidirectional data stream corresponds to a bidirectional data stream (also called bidirectional binding ).

In-depth understanding of the node. js http module, and in-depth understanding of node. js The http module is mainly used to build an HTTP server and client. The HTTP module must be called to use the http server or client functions. Create a server Var http = require ("http"); var url = require ("url"); // create a server // http inherits from tcpvar server = http. createServer (function (req, res) {var url

In-depth understanding of display attributes-common important attributes of front-end layout, and in-depth understanding of display Note: The display attribute is very common in web page layout, but it is often used only a few attribute values, such as block, inline-block, inline, And none. I will introduce each aspect of the display attribute in detail below.Definition The display attribute specifies the b

In the video teaching after the understanding of learning, if the wrong to ask the great God adviceA type conversion in the C # language is the conversion of one data to another type of data.The data types in the C # language are mainly:Char type (character type);Type string (string type);int type (integer type);Double type (decimal type);Type conversions are divided into three main types:1: Convert any type to string type;The conversion code is writt

picture to express the change of the three prototype references. In the heap, the right side is the memory representation of the function object, the middle is the point of the prototype property of the function object, and the left is the object instance created by the function object. Where the function object points to the prototype property, it writes dog1,dog2,dog3 three reference changes corresponding to the Dog.prototype respectively. They also have a corresponding relationship with the

The previous blogs focused on Hadoop's storage HDFs, followed by a few blogs about Hadoop's computational framework MapReduce. This blog mainly explains the specific implementation process of the MapReduce framework, as well as the shuffle process, of course, this technical blog has been particularly numerous and written very good, I wrote a blog before the relevant reading, benefited. The references to some blogs and materials will only be listed in the resources below. MapReduce

Understanding and simple implementation of Spring Aop, springaop understanding1. The Aspect-Oriented Programming mentioned in the AOP concept is actually a set of actions when processing a series of business logic. For example, to connect to the database: load the driver ----- get class -------- get the connection object ------- access the database ------ query --------- operation results for the above series of actions we regard the dotted line as a

Format:(function () {//code}) ();The first pair of parentheses of the enclosing function (function () {}) returns an unnamed function to the script, followed by a pair of empty parentheses that immediately execute the returned unnamed function, which is the parameter of the anonymous function in parentheses.(function (ARG) {alert (arg+100);}) (20);This example returns 120.Come back to see jquery plugin writing(function ($) { //Code Goes here}) (JQuery);This code is equivalent tovar A=functon ($

Recently, some good articles have been found on overseas websites, collected and sorted for your own understanding, recorded as notes, so that you can have memories in the future.ASP. NET is a very powerful platform for building Web applications. It provides great flexibility and capabilities so that it can be used to build all types of Web applications. most people are only familiar with high-level frameworks such as WebForms and WebServices. the. NE

, single-case1. Instance variable: the instance variable belongs to the class object, that is, the object instance is private and is allocated in the heap of the virtual machine.2. Verify thread security for instance variables:(1) From the program, we can see that when the singleton mode, there is a resource conflict, when not a singleton mode, there will not be a thread conflict.(2) Program operation result diagram:Figure 1:Figure 2:3, the conclusion: the instance variable is the instance objec

Last time is a note on a chat item, inside the socket is also involved in a lot. So what is a socket?The two programs on the network realize the exchange of data through a two-way communication connection, one end of this connection is called a socket.In layman's terms, I think it is a connector that connects the two. The English meaning of the socket is "hole" or "socket". He's the equivalent of that socket, connected to the communication between different virtual machines or different computer

(pSpatialFilter, True) Use Cursor to access records Now you have a good understanding of the general mechanism for generating cursor. Let's see how to use a cursor to access the returned records. Remember, cursor is a set of records from only one table or element class in memory. When a cursor is generated for the first time, an associated pointer is also generated. You can use a cursor to access a row of records at a time. This pointer helps you tra

The following things are not what I have created. They are the essence of some books I think. After learning about JavaScript, I feel that my understanding of JavaScript has been further improved, find out something that is also known as a trick or a trick. I will apply this knowledge to a new framework. The goal of the new framework is to use js to display various charts. Although there are already many frameworks with this function, however, I think

Understanding the emulator's limitations Although the new simulator keeps up with the development of devices and ensures high-fidelity simulation of devices and the convenience of developers, each simulator has some limitations when simulating real devices. The smartphone code run by the simulator in the smartphone SDK is compiled for the x86 CPU. In most major application development scenarios, this is enough to meet the requirements. However, this t

Coredata first class understanding coredata, coredata first class understandingProblem There are many ways to persistently store data in iOS/Mac: NSUserDefault, Key chain, C language file interface, NSFileHandle, write method in basic framework, archive, and so on. In practical applications, we often need to convert the data into objects in a certain format, and perform certain filtering and other operations before using them, which is not very conven

forced conversion operation to convert it to object. Forced conversion does not change B object, but your B object view limits the data and behavior to. After B is forcibly converted to a, the can be forcibly converted to B. If Class B is used as Class B, data and behavior of Class A and Class B can be obtained at the same time. Objects can represent multiple types of capabilities called polymorphism. by understanding these concepts, you can define

of 0x013. However, the status in registers and memory remains the value set by the addl command until the next cycle begins. [In this example, the clock is used to control the update of State elements and the value is transmitted by the combination logic. It is enough to control our SEQ to implement the computation of every instruction execution. Each time the clock changes from low to high, the processor starts to execute a new command .] 【Read operations are transmitted along these units, a