• Fast jump tool — a brief introduction to FASD


    preface FASD is a command line acceleration tool. It provides fast access to files and folders. It’s very similar to autojmp, Z, V. It will record the folders and files you have visited, and then you can access them directly by short names.FASD will sort the accessed files and folders by frequency of use, and […]

  • Data structure — select sort


    A go implementation of selective sorting package main import “fmt” //The core of selective sorting is to exchange the maximum or minimum values of the following len (ARR) – n elements in the array with the nth element for the nth time func selectSort(arr *[5]int){ for j := 0; j < len(arr) – 1; J […]

  • Meaning of Mongo slow log field


    View the slow log configuration of the current clusterdb.getProfilingStatus(); // If slowms: indicates the time of slow log configurationdb.getProfilingLevel(); // Indicates whether to write the slow log to the system table db.system.profile. 0 means off, 1 means on. Lock mode of MongoMode DescriptionR representatives shared (s) lock. / / sharedW representatives exclusive (x) lock. / […]

  • Question 42: what is the JS garbage collection mechanism?


    JS memory life cycle Allocate the memory you need Use allocated memory (read, write) Release and return them when they are not needed What is garbage collection mechanism? The garbage collection mechanism is to find out those values that are no longer used, and then release the memory space occupied by them. The garbage collector […]

  • BMS (battery management system) lesson 3 – BMS function list and sampling requirements


    BMS function list In personal habits, BMS functions are divided into three parts Basic functions of BMS: V / I / T sampling, protection function (overvoltage, overcurrent, overtemperature, insulation resistance), relay drive, status sampling, relay adhesion detection, can communication; Core functions of BMS: cell balance, SOP (power), SOE (energy), SOC (state of charge), SOH (Health); […]

  • Statistics of user access times for hive basic operations


    preface According to several pieces of data on user ID, access date and access times, the cumulative access times of each user are analyzed, involving string replacement, time function, windowing, summation and other technologies. 1. If a user accesses data (user ID, access date, access times) userId visitDate visitCount u01 2017/1/21 5 u02 2017/1/23 6 […]

  • [PHP data structure] linear search and binary search


    Welcome to the world of search. After learning all kinds of data structures, you have finally come to this step. What do you think? Anyway, I forget while learning. Now let me talk about the algorithms of graphs, which are still in the state of circles. However, learning is step by step. In fact, things […]

  • [go] golang exercise project – go realizes bubble sorting and optimization algorithm


    Core principles: Comparing two adjacent elements, the larger one moves to the right Optimization: The ordered elements are no longer compared, and the comparison times are reduced The variable flag of the following function is used to judge whether the subsequent elements are exchanged. If there is no exchange, the traversal will be stopped directly […]

  • Problems of SQL statements in Oracle


    1. A method of splicing a field of multiple queried records into a string in Oracle Listagg: (19C is also available) select listagg(name,’,’) within (order by id) from table In 10g, WM is used_ concat: select wm_concat(name) from table wm_ Concat is undocument Listagg is the name of 11g document 2. Select the record with […]

  • A function that counts the number of occurrences of one string in another string


    Function strnum(patrn, strng)   Dim regEx, Match, Matches,xx     xx=0   Set regEx = New RegExp   regEx.Pattern = patrn    regEx.IgnoreCase  =  True             ‘  Sets whether the is case sensitive.  regEx.Global = True   Set Matches = regEx.Execute(strng)   For Each Match in Matches     xx=xx+1   Next   strnum = xx End Function

  • Intersection of two arrays of large factory interview algorithm


    Given two arrays, use a function to calculate the intersection of the two. let num1 = [1,2,2,1]; let num2 = [2,2]; //Find [2,2] let num1 = [4,9,5]; let num2 = [9,4,9,8,4]; //Find [4,9] Method 1 Save hash table Since the same number may appear more than once in both arrays, you need to use a […]

  • Complexity of data structure


    1、 Algorithm efficiency There are two kinds of algorithm efficiency analysis: 1. Time efficiency Time efficiency is also called time complexity. It mainly measures the running speed of an algorithm. 2. Space efficiency Spatial efficiency is also called spatial complexity. It mainly measures the additional space required by an algorithm. In the early stage of […]