• Usage of call(), apply(), bind() in JavaScript


    In fact, it’s a very simple thing. After watching it carefully for ten minutes, you can get a complete understanding from a confused B on your face! First see the following: Example 1 obj. objAge;   // 17obj. Myfun() / / Xiao Zhang’s age is undefined Example 2 Shows() / / blind monk Compare the […]

  • Fast bidirectional data binding in 10 minutes


    concept In fact, the concept of two-way binding is very simple, that is, the change of view can change the data model in real time, and the change of data can also be updated to the view layer in real time. What we call one-way data binding is the relationship from data to view. analysis […]

  • 9.2 basic query


      9.2.1 query all columns *Represents all columns ##Query all employee information Select * from emp;   9.2.2 query specified columns Enter the individual column name in the special table for query Select empno,ename,depton from emp;   9.3 query criteria where 9.3.1 common operators Relational operators: =,! =, < >, > =<= Interval: between a […]

  • Compare excel and use pandas to analyze various usages of data


    background Understanding programming language first belongs to the world of programming apes. Now, with the improvement of domestic people’s education and the development of Internet technology, business personnel also begin to need to understand programming language slowly. Judging from the recruitment demand in recent years, python has become a rigid demand. Most of the business […]

  • Using C # to realize data structure heap


    1、 Introduction to heap: Heap is used for sorting. It is usually an array object that can be regarded as a tree. The heap meets the following characteristics: 1. The value of a node in the heap is always not greater than or less than the value of its parent node The value of any […]

  • String in ES6


    String has always been the data with high usage in the programming language. Although the function is a first-class citizen in JS language, how can string be regarded as the second of the millennium? Let me discuss with you some new usage and features in ES6, especially in string splicing, which will liberate the eyes […]

  • JVM – four ways for objects to enter the old age – 2 (practical part)


    Four ways for objects to enter the old age After minor GC, the space in the survivor area cannot accommodate all surviving objects The surviving object reached the age threshold. Like 15 Large object Dynamic age judgment In this section, the main topic is that the surviving object reaches the age threshold. Like 15. Of […]

  • Instead of H5, use pywebio module to realize web page directly


    The biggest advantage of pywebio is that it can write web pages like terminal scripts, and obtain users’ input and output at the browser level by providing a series of interactive functions. [read the full text] Running effect under pycharm editor Running effect under IPython editor Installing the python web plug-in pip3 install -U pywebio […]

  • Spring boot quick start (V): use mybatis (annotation form) for database operation


    Add dependency For the new project, select three dependencies: Web, mybatis and mysql For existing projects, you can use bulid Add gradle and spring boot will help you configure it automatically compile(‘org.springframework.boot:spring-boot-starter-data-jpa’) compile(‘org.springframework.boot:spring-boot-starter-web’) runtime(‘mysql:mysql-connector-java’) testCompile(‘org.springframework.boot:spring-boot-starter-test’) Basic configuration information Then in Src / main / resources / application Add basic configuration under properties #Database connection address […]

  • Unexpectedly, python can also make web visualization pages!


    This article is forwarded from:blog.csdn.net/KH_FC/article/detail…When it comes to web pages, you may first think of HTML, CSS or JavaScript.This little f will introduce you how to make a data visualization web page with Python, using the streamlit library.Easily convert an Excel data file into a web page for everyone to view online.Whenever you save changes […]

  • Review of constructors and adding constructors to the array prototype chain


    charset=”utf-8″> Content in console //Create constructor function Test(name){ this.name = name; this. XBC = < font color = “#ff0000” > < font color = “#ff0000” > < font color = “#ff0000” > ‘< / font > < span style = “background color: RGBA (245, 245, 245, 1)” > What are you looking at</ span></font><font color=”#ff0000″>'</font>;</ […]

  • Practice mongodb operation – data operation (I)


    The goal of this article is to better understand if through a large number of examplesMongodbData operation in; First in clientJust usemongodThe command enters the client environment and knows nothing about the database at this time; Look around and want to know what databases there are now, show dbs; Because it’s newmongodbEnvironment, so I only […]