• Case analysis of positive and negative prefetch in regular expressions


    In this paper, the positive and negative pre queries in regular expressions are illustrated. Share with you for your reference. The specific analysis is as follows: Here’s an example to explain what a forward lookup is. Example: there is a paragraph called “coming soon, going go gogogo”, which requires finding out com and go. The […]

  • Using jsonpath in fastjson to process JSON data


    introduce The version after fastjson 1.2.0 supports jsonpath. , which can be used as the JSON object query language (OQL) in the Java framework. Common API public class JSONPath { //Evaluation, static method public static Object eval(Object rootObject, String path); //Evaluation, static method,按需计算,性能更好 public static Object extract(String json, String path); //Calculate size, number of map […]

  • SQL number to Chinese uppercase


    USE [SPECIAL_BLD]GO SET ANSI_NULLS ONGO SET QUOTED_IDENTIFIER ONGO CREATE FUNCTION [dbo].[get_upper] ( @num numeric(18,5))RETURNS VARCHAR(500)ASBEGIN DECLARE @n_data VARCHAR(20),@c_data VARCHAR(100),@n_str VARCHAR(10),@i int SET @n_data=RIGHT(SPACE(14)+CAST(CAST(ABS(@num*100) AS bigint) AS varchar(20)),14) SET @c_data=” SET @i=1 WHILE @i<=14 BEGIN SET @n_str=SUBSTRING(@n_data,@i,1) IF @n_str<>’ ‘ BEGIN IF not ((SUBSTRING(@n_data,@i,2)=’00’) or ((@n_str=’0′) and ((@i=4) or (@i=8) or (@i=12) or (@i=14))))Set @ c_data […]

  • 61. Rotating list


    Given a list, rotate the list, and move each node of the list to the right by K positions, where k is a non negative number. Example 1: Input: 1 – > 2 – > 3 – > 4 – > 5 – > null, k = 2Output: 4 – > 5 – > 1 […]

  • Common indicators of semantic segmentation


    There are three most commonly used indicators in semantic segmentation. To facilitate interpretation, the confusion matrix needs to be introduced first, as follows: Confusion matrix True value Positive Negative   predicted value   Positive True positive (TP) False positive (FP) Negative False negative (FN) True negative (TN)   First of all, it is assumed that […]

  • Implementation of negative number in the bottom layer of computer


    Do you really understand negative numbers in Java? From http://blog.csdn.net/candyguy 1、 How to code negative numbers in Java? Java uses “two’s complement” to encode negative numbers. It is a numerical encoding method, which needs to be completed in two steps: first, each binary bit takes the opposite value, 0 becomes 1, 1 becomes 0. For […]

  • How much do you know about border radius?


    Before the appearance of the CSS3 property border radius, we must draw a circle on the page with the help of pictures. After the border radius property, it is very easy for us to realize a circle on the page. Next, let’s study this border radius carefully to see what kind of black magic does […]

  • Technology sharing | thinking about MySQL show processlist with negative time


    Author: Gao PengAt the end of the article, there is his book “in-depth understanding of MySQL master-slave principle 32”, in-depth understanding of MySQL master-slave, gtid related technical knowledge. 1、 Source of problem This is a question that a friend asked me. The question is as follows: what happens when the worker thread sees that time […]

  • C Language: Modular Operation between Positive and Negative Numbers (Reprint)


    If the operands on both sides of% are positive, the result is positive or zero; if the operands on both sides of% are negative, the result is negative or zero. Before C99, it was not stipulated what the result of modular division would be if one of the operands was negative. C99 stipulates that if […]

  • Negative Number and Binary Conversion Method


    1. Conversion of decimal negative numbers to binary numbers Assuming that there is a number of int types with a value of 5, we know that it is represented in the computer as follows: (because in Java int is 4 bytes, so the high bit needs to be filled with 0, accounting for 32 bits)00000000 […]

  • A brief look at the source code, complement code and counter code


    Recently, there have been so many thieves who haven’t had much time to write blogs and haven’t updated blogs for a long time. But when I look at the JDK source code, I have a great feeling that the foundation is really important, so what is the foundation? In addition to the basic grammar of […]