• Scala, a “maverick” language!


    <!– Scala, a “maverick” language! — > It’s hard not to touch Scala on the way to spark. Scala seems to provide a lot of “functional programming like” syntax candy for Java. Here are some unique parts of the language to share with readers. Reference materials mainly include: Cao Jie. Spark big data analysis technology […]

  • An article takes you to understand the “string class” of the basic algorithm in JavaScript


    Author | jeskson Source: dada front end Tavern 1 What can algorithms do? Improve what? What are the benefits? Front end students need to improve their core skills in programming, establish and improve the knowledge system of algorithms, basic algorithms, data structures and advanced algorithms, explain from simple to deep, and thoroughly understand abstract algorithms. […]

  • Es new features


    es6: https://es6.ruanyifeng.com/ es6-es12: https://segmentfault.com/a/11… Block level scope let, const (reference address cannot be changed) Deconstructing assignment and extension operators Template string“ /*Tagged template string*/ function foo(a, b, c) { console.log(a, b, c); } let name = ‘Jack’; let age = 18; Foo ` my name ${name}, age ${age} ‘; Arrow function Dynamically import (modulename). Then […]

  • Laravel quick reference manual


    Common statements Helper function path \vendor\laravel\framework\src\Illuminate\Support\helpers.php config(‘app.cdn_ Domain ‘) read configuration env(‘CDN_ Domain ‘) read only in configuration files $path = app_ path(); Return the app path C: \ www \ laravel \ app, $path = base_ path(); Project root directory, C: \ www \ laravel $path = config_ path(); Configuration path C: \ www […]

  • Sequential representation of linear table — sequential table


    1. Definition of sequence table The sequential table uses a group of storage units with continuous addresses to store the data elements in the linear table in turn. Logically adjacent elements are stored in storage units that are also adjacent in physical locations, and the relationship between elements is reflected by the adjacency relationship of […]

  • JS / TS de duplicates the objects in the array according to the value of the object


    For example: de duplicate the following array according to the value of LastName let listData = [ { firstName: “Rick”, lastName: “Sanchez”, size: 18 }, { firstName: “Morty”, lastName: “Smith”, size: 6 }, { firstName: “Jerry”, lastName: “Smith”, size: 3 }, { firstName: “Beth”, lastName: “Smith”, size: 0 }, { firstName: “Summer”, lastName: “Smith”, size: […]

  • Java foundation — in-depth understanding of collections


    Java Foundation Set: After summarizing for a long time, it is found that it is still summarized from the perspective of interface, which is relatively clear. Therefore, 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 […]

  • Bfe.dev front end brush questions #9. Decrypt messages (Facebook interview questions)


    Bfe.dev is a question brushing website for the front end, such as leetcode. This series of articles is my diary above. Topic 9 Bfe.dev#32 9. Decrypt message In a two-dimensional array of strings, there is a hidden string. I B C A L K A D R F C A E A G H O […]

  • Leetcode78. Subset Python implementation


    Title Requirements: Idea: Define a res to save the result set Traverse the array, add the current value to all values in the res result set, and then append to the result set. After traversing the array, res appends a [[]], which is the result Core code: res = [[]] for i in range(len(nums)): for […]

  • Es5 common array methods


    The following array methods are sorted join() Push() and pop() Shift() and unshift() sort() reverse() concat() slice() splice() Indexof() and lastindexof() (new in Es5) Foreach () (new in Es5) Map () (new in Es5) Filter () (newly added in Es5) Every () (Es5 added) Some() (new in Es5) 1|0 join() Join is to convert an […]

  • Read file names from a file in Bash and check that the current directory protects these files


    Purpose: read the file name from a file in Bash, check all files in the current directory, and return a prompt if they do not existImplementation: check_ file.sh #!/bin/bash #Get current path CRTDIR=$(pwd) i=0 #Get the file name from the txt file with the file name saved, and generate an array for line in $(cat […]

  • ES6 Usage Summary


    Destructuring assignment Realize variable exchange let a =1; let b=2 [a,b]=[b,a] console.log(a,b)//2,1 Default value assignment [a,b,c=3]=[1,2] console.log(a,b,c)//1,2,3 Get function return value directly function fc(){ return [1,2] } let a,b; [a,b]=fc() console.log(a,b)//1,2 Nested deconstruction assignment of objects let metadata={ title:’currentTitle’, test:[{ title:”deepTitle”, desc:’description’ }] } let {title:titleone,test:[{title:titlescond}]}=metadata; console.log(titleone,titlescond)//currentTitle,deepTitle String extension If the Unicode code is greater […]