• New features of interview question ES6 (detailed)


    There are many new contents in ES6, and they are often used in development. With various Babel transformations, most companies in the market are developing with ES6 syntax. JavaScriptIt’s said that Netscape companyBrendan EichDashen designed it in 10 days. Leaving aside the topic of designing a programming language in a short time, no language is […]

  • JavaScript on the front end


    JavaScript JavaScript is a scripting language, which is mainly composed of the following three parts: Core (ECMAScript) Document object model (DOM)   Document object model (integrating JS, CSS, HTML) Browser object model (BOM) Note: ES6 refers to ECMAScript 6. Introduction of JavaScript //First, write code in the script tag JS code //Second, introduce JS file […]

  • Custom UDF function vector_ Trans: traverse two arrays and turn them into target vector arrays (xgboost model)


    vector_ Development and optimization of trans UDF function 1、 Background Under the group data mining project, user portrait project needs to develop some basic tags, such as age, gender, marital status, car ownership, house ownership, assets, etc. These tags can not simply use the data under the group as the final evaluation result, because the […]

  • Redux source code interpretation — composition source code analysis


    Composition source code analysis composeModule code is very concise, but the role of the implementation is very powerful.reduxWhy Redux? Some people say it isreduceandfluxThe combination of the tworeduceExactlycomposeThe core of the module. composeThe function of the module is powerful and simpleFrom right to left, combine parameters (functions).So, pass it on tocomposeMethod parameters must be of […]

  • Record the callback functions (asynchronous and synchronous problems) encountered by arr.map and arr.foreach


    The general question is:Through the callback function of map or foreach loop, the array is operated,There are Ajax asynchronous functions inside the callback function, which are called by await synchronous writing. The array printed by console.log is always inconsistent with the page actually rendered to the view layer.It’s just a for loop. So to sum […]

  • Java foundation — deep understanding of collection


    Java Foundation Set: After summing up for a long time, I found that it was clear to summarize from the perspective of interface, so this article mainly analyzes the collection from the perspective of interface* 1. Single column collection (collection interface) The collection interface is the parent interface of all single column collections. It also […]

  • Using reduce () method to process tree data


    definition: reduce()Method performs a task provided by you for each element in the arrayreducerFunction (executed in ascending order) to aggregate its results into a single return value. Like foreach(), map(), and filter(), reduce() will traverse every item in the array, but reduce() can calculate the result of the previous array item and the current one. […]

  • JavaScript Basics


    —–JS Introduction to JS Provided by Netscape (Netscape) company, the script language embedded in the browser is responsible for realizing the animation effect in the web page, or realizing the form verification and other functions. JS features and advantages 1. Features:(1) JS is a literal translation language (Interpretation and execution, no compilation process)When writing, XX. […]

  • Review four basic data structures: array, linked list, queue and stack


    preface This article is included in the album:http://dwz.win/HjK, click to unlock more knowledge of data structure and algorithm. Hello, I’m brother Tong, a hard core man who climbs 26 floors every day and doesn’t forget to read the source code. Array, linked list, queue and stack are the most basic four structures in data structure. […]

  • JavaScript — common built-in objects


    Everything in JavaScript is an object: string, number, array, function In addition, JavaScript also provides multiple built-in objects, such as array, date, math, etc Objects are just special data types with properties and methods         1、 Array object array Array objectThe function of is: use a separate variable name to store a […]

  • Have Fun with Numbers


    subject   Topic link      The first time to do all English programming (vocabulary is seriously insufficient, also need to remember more words); The general meaning of the title is: enter an integer with no more than 20 digits, multiply the number by 2, and compare the results before and after calculation to see if […]

  • Map for easy understanding of data structure


    preface Original intention:I’ve been reading recentlyDeep understanding of ES6This book, I haven’t learned ES6 grammar thoroughly before, so I’ll read it again when I’m not busy. I’ll share my notes with you. Don’t spray if you don’t like it. Suitable for people:The primary development of the front-end, big man detour. Content structure:Understanding Map > basic […]