• New JavaScript syntax “double question mark syntax” and “optional chain syntax”


    Double question mark grammar Double question mark grammarThe concept is to return the value on the right when the value on the left is null or undefined let Form = undefined ?? true; //Form = true Alternative chain syntax ? optional chain //Optional chain let body = { value: { a: ‘123321’ } } let […]

  • 13-1-3 password management


    Password management in Django Password management is not reinvented when it is not necessary. Django is committed to providing a set of secure and flexible tools to manage user passwords. This document describes how Django stores passwords and hash storage method configurations, as well as some examples of using hash passwords. See also Even if […]

  • Using native JS to write multiplication table


    Step idea: 1. Use for loop to print 99 multiplication table2. 9 rows and 9 columns, double for, empty string, escape character spacing tab, newline3. Variable storage — number, row, column Show one function getForm() { var num = ”; for (var rows = 1; rows <= 9; rows++) { for (var cols = 1; […]

  • [flutter tool] is probably the simplest local data storage scheme on flutter


    brief introduction local_cache_syncIt’s a very simple and easy to use oneFlutterLocal repository, suitable for storing a list of lightweight data locally (for example, the configuration of a series of Bluetooth devices saved locally by users, or caching a series of user information) local_cache_syncAll methods, including save and read, aresynchronizationYes, notasynchronousYes. Synchronous accessIt means you don’t […]

  • Sum with native JS


    (1) Find the sum of all numbers within 100 divisible by 3 and 7 /*Step: use variable to store target number accumulation sum For sets the body of the loop If setting meets the condition*/ var sum = 0 for (var i = 1; i <= 100; i++) { if (i % 3 == 0 […]

  • Fault characteristics of flash memory


    Flash memory is a kind of nonvolatile semiconductor memory based on floating gate technology, which generally has several types, such as nor, NAND, dinor and. As a kind of nonvolatile memory, flash memory has its own unique advantages: it can be electrically erasable and reprogrammed without special external high voltage, low cost and high density, […]

  • JavaScript prints the leap year of a given interval year


    requirement: The user inputs the year interval, start year and end year to be judged, and outputs all leap years in the interval. Code implementation: function isRunYear(year) { //Return true for leap year, otherwise return false var flag = false; if (year % 4 == 0 && year % 100 != 0 || year % […]

  • Using native JS to write microprogram


    (1) Simple ATM /*Steps: 1. Print the directory to the user 2. The variable stores 100 yuan of money left 3. Variable storage = save money: enter the amount of money plus the previous amount of money saved, and the balance prompt box will pop up 4. Variable storage = withdrawal: subtract the withdrawal from […]

  • How to make fram MCU faster and need the lowest power consumption


    Why can MCU with fram have many advantages? For example: Ti has done an experiment. If it needs to write 13kbps data to DRAM, it will take 1 second, about 2200ua power consumption to do the writing function. But if it uses fram, it only needs 10ms, 9ua to finish the data writing. Through comparison, […]

  • SDRAM power source


    In modern communication and image data processing system based on FPGA, large capacity and high speed memory are often used. SDRAM has a synchronization interface, which will wait for a clock signal before responding to the control input, so that it can synchronize with the system bus of the computer. Among all kinds of RAM […]

  • Capacity expansion of SRAM


    SRAM is static random access memory. The so-called “static” means that as long as the memory is powered on, the data stored in it can be kept all the time, but it will be lost after power failure. Compared with DRAM (dynamic random access memory), it doesn’t need to refresh the data periodically. It’s easy […]

  • Using redis in springboot


    When our project needs to use caching and high concurrency, we can use redis connection pool, let’s go straight to the topic. The project environment of this paper is win 10, springboot 2.1.5.release, redis java client jedis 2.9.3, fastjson 1.2.47 (for serialization). This project uses the Lombok plug-in, so the set and get methods are […]