• chopstick


    Chopsticks are shaped pairs of equal-length sticks. They are smoothed and frequently tapered and are commonly made of bamboo, plastic, wood, or stainless steel. They are less commonly made from titanium, gold, silver, porcelain, jade, or ivory. Chopsticks are held in the dominant hand, between the thumb and fingers, and used to pick up pieces […]

  • Detailed explanation of Chinese problems in java/jsp


    Preliminary knowledge: 1. Bytes and UnicodeThe Java kernel is Unicode, even class files, but it is very multimedia, including the way to save files / streamsIt uses byte stream. Therefore, Java needs to convert these bytes through the line. Char is Unicode and byte is byteThe function of byte/char conversion in Java is in sun There […]

  • Installing and uninstalling jdk8


    Foreword: the first step to learn Java is to configure the JDK environment, and jdk8 is the most widely used JDK version at present. This article explains how to download, install, and uninstall jdk8. The following environments are windows10 Download JDK installation package Oracle official website All JDK versions (Oracle official website) Jdk8 (Oracle official […]

  • Summary of time related knowledge points in c\


    Summary of time related knowledge points in c\ 1、 English abbreviation of month DateTime dt = DateTime.Now; string MM = dt. AddMonths(-1). ToString(“MMM”, new System.Globalization.CultureInfo(“en-us”));// English abbreviation of month: Jul 2、 First and last day of the month DateTime ThisMonth_Frist = DateTime.Now.AddDays(1 – DateTime.Now.Day).Date; DateTime ThisMOnth_Last = DateTime.Now.AddDays(1 – DateTime.Now.Day).Date.AddMonths(1).AddSeconds(-1); 3、 First and last day […]

  • First day of java learning


    Markdown learning title For several level titles, add a few pound marks at the beginning of the title, and it can only reach six level titles at most. typeface Using shortcut keys quote Greater than sign plus space to generate reference effect Split line Three asterisks or three minus signs picture Exclamation point plus English […]

  • MySQL row to column, column to row


    1、 Row to column That is, the different contents of multiple rows under the same column are used as multiple fields to output the corresponding contents. Create table statement DROP TABLE IF EXISTS tb_score; CREATE TABLE tb_score( id INT(11) NOT NULL auto_increment, Userid varchar (20) not null comment ‘user id’, Subject varchar (20) comment ‘account’, […]

  • Summary of methods for programmers to quickly query API documents


    1、 Borrow Google scope search Setup steps Right click the chrome address bar and select manage search engine Add a search engine and add the following contents (set the starting keywords) Rookie tutorial https://www.google.com/search?newwindow=1&biw=1920&bih=974&noj=1&q=%s+site%3Ahttp%3A%2F%2Fwww.runoob.com%2F&oq=%s+site%3Ahttp%3A%2F%2Fwww.runoob.com%2F&gs_l=serp.12…28391.28675.0.30427.….0…1.1.64.serp..2.0.0.cP6AQPTxH68 mdn https://www.google.com/search?rlz=1C1CHWL_zh-cn__848__848&ei=ovkIXYGGBKyw0PEP0vG72Ag&q=%s++site%3Ahttps%3A%2F%2Fdeveloper.mozilla.org%2Fzh-CN&oq=%s Advantages of runoob Support for multiple languages(JavaScript, typescript, CSS, HTML, GIT, liunx command, jQuery…) Chinese Support online testing Recommended […]

  • MySQL cannot insert [err] 1064 – you have an error in your SQL syntax- Laidada


      Error [err] 1064 – you have an error in your SQL syntax; When writing PHP, msyqli inserts data after writing, and the error is always reported. After copying to Navicat, the error is still reported. [err] 1064 – you have an error in your SQL syntax; Uncomfortable insert into order (Oid,user_id,Odate,Onum,Tid,states) values (‘1612715211′,’1612715212′,’2021-02-01 02:28:02′,’9′,’1612715213′,’2’) […]

  • Install and configure multiple versions of JDK


    Preface: there are multiple versions of JDK. Sometimes it is necessary to switch different versions for development. To install multiple jdks on a computer, you only need to configure them as follows, and you can easily use them each time. The following environments are windows10 Install JDK Install jdk8 Configure environment variables Configuration requiredJAVA_HOME CLASSPATH […]

  • 2021 rust survey results released: a total of 9354 questionnaires were collected


    Recently, rust announced the results of the 2021 survey, which was launched in December 2021. The results are based on the cumulative statistics of 9354 questionnaires. Global community The rust community continues to grow and the number of complete survey responses to this survey is the highest in history (9354 respondents), about 1500 higher than […]

  • Start your first machine learning project with Python


    1. Install Python Install Python – M PIP install — user numpy SciPy Matplotlib IPython Jupiter pandas Symphony nose pip install -U scikit-learn design sketch:   Operation results:     Full code: from pandas import read_csv from pandas.plotting import scatter_matrix from matplotlib import pyplot from sklearn.model_selection import train_test_split from sklearn.model_selection import cross_val_score from sklearn.model_selection import […]

  • SQL must know and be able (basic concept)


    1、 We can divide the SQL language into the following four parts according to its functions: DDLIn English, it is called data definition language, that is, data definition language. It is used to define our database objects, including databases, data tables and columns. By using DDL, we can create, delete and modify database and table […]