• Experiment of adding, deleting, checking and modifying database in mongodb


    Mongodb database experiment 1: Add data Operation 1: single insert: the user dataset inserter in yelp database and the data required as follows A kind of ID: self defined class; user_ ID: own student number + any character (more than 22 characters take the first 22 digits, less than 22 characters add letters, numbers or […]

  • JS regular is enough


    In our actual projects, we often encounter some common regularization methods. Here we will sort them out and update them in the future.(welcome to collect and add) Common regularization methods export const regExpConfig = { Mobile: / ^ 1 ([3 | 4 | 5 | 7 | 8 |] \ D {9} $/, // mobile […]

  • Data type in Oracle: parameters of VARCHAR2


    VARCHAR2 (byte) stores bytes. VARCHAR2 (char) stores characters.   VARCHAR2 (2 byte) can store up to 2 bytes, and VARCHAR2 (2 char) can store up to 2 characters.   When the database character set is: 1. ForAL32UTF8One Chinese character is one character, and one Chinese character occupies one3VARCHAR2 (2 byte) can not save one Chinese […]

  • C practical exercises 27


    Title:Using recursive function call method, the input 5 characters are printed out in reverse order. Program analysis:None. example: #include int main() { int i=5; void palin(int n); Printf (“please input 5 characters, 40: 40”); palin(i); printf(“\n”); } void palin(n) int n; { char next; if(n<=1) { next=getchar(); Printf (“output results in reverse order: 40:40”); putchar(next); […]

  • “Selfie tutorial 49” Python_ ADB batch character input


    Android terminal product system or app test involves input box boundary value test,For example, WiFi hotspot setting hotspot name, or search input box,You need to verify that the text input box can input up to 256 characters,How to quickly realize the input of 256 characters? Preparation stage Manually click the WiFi hotspot name text input […]

  • Java serialization 97 fileoutputstream detailed explanation and file copy


    1、 Filetoutputputstream 1. The construction method of this class has the second parameter FileOutputStream(String address,boolean append) Append defaults to false, which means that new writes will override the original. If it is changed to true, the file is written in the form of appending   package com.bjpowernode.java_learning; import java.io.*; public class D97_1_FileOutputStream { public static […]

  • [Issue 2] selected front end algorithms – string series


    Today’s selected topic is about string operation, involving the skills of string sliding window thinking, large number multiplication. Arrangement of strings Leetcode.567, medium difficulty subject Given two stringss1ands2Write a function to judges2Is it includeds1The arrangement of. In other words, one of the permutations of the first string is a substring of the second string. Example […]

  • 100 MySQL interview questions for Linux operation and maintenance (2)


    Continue to the previous article: 100 MySQL interview questions for Linux operation and maintenance (1) 21. Delete all the data in the test table and view it delete from test; select * from test; 22. Delete the table test and mingongge database and view it drop table test; show tables; drop database mingongge; show databases; […]

  • Regular expressions (JavaScript)


    JavaScript regular expression Character matching Metacharacters for common matching characters: .Matches any character except newline. \wMatch letters or numbers or underscores or Chinese characters. \sMatches any whitespace. \dMatch numbers. \WMatch any character that is not a letter, number, underline, or Chinese character. \SMatches any character that is not whitespace. \DMatches any non numeric character. [0-9]and[^abc]They […]

  • 100 MySQL interview questions of Linux operation and Maintenance Conference (2)


    Next: 100 MySQL interview questions of Linux operation and maintenance meeting (1) 21. Delete all data in the test table and view delete from test; select * from test; 22. Delete the table test and mingongge database and view drop table test; show tables; drop database mingongge; show databases; 23. Do not exit the database […]

  • Input verification of lapis


    Input validation Verification case LapisA set of validators for processing external inputs is included. Here is a simple example: local lapis = require(“lapis”) local app_helpers = require(“lapis.application”) local validate = require(“lapis.validate”) local capture_errors = app_helpers.capture_errors local app = lapis.Application() app:match(“/create-user”, capture_errors(function(self) validate.assert_valid(self.params, { { “username”, exists = true, min_length = 2, max_length = 25 }, […]

  • [20191011] split ROWID 2.txt


    [20191011] split ROWID 2.txt –//With the link http://blog.itpub.net/267265/viewspace-2659612 / = > [20191011] bash arbitrary base code table.txt–//It’s very easy to convert and split ROWID in bash. Write a script yourself –//Row ID format: oooooofffbbbbbbrrr, 6 characters for data object ID, 3 characters for file, 6 characters for block and 3 characters for row. Of course, […]