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1, How to set utf8mb4 up For string types in mysql, charset can be set exactly to the field. If only one field is set utf8mb4, other fields will not be affected. If it is set for the table, the existing field will still be utf8, and there will be more utf8 tags, and then the created field will be utf8mb4. If it is set for the library, the e ...

1. ?? Non air operator In JS,?? Operators are called non airlift operators. If the first parameter is not null/undefined, the first parameter will be returned, otherwise the second parameter will be returned. For example, null ?? 5 // => 5 3 ?? 5 // => 3 When setting default values for variables, logic or operators were commonly used, ...

In this chapter, we will take the picture crawler as an example to explain how to implement the picture crawler project through the Scrapy framework.Review with urlib handwritten crawler:Previously, in actual combat, urlib was used to handwrite the picture information of crawling JD mobile phone. Here I'll write a simple keyword climbing area ...

preface This learning note is the learning content of Alibaba cloud Tianchi Longzhu plan machine learning training camp. The learning links are: https://tianchi.aliyun.com/specials/promotion/aicampml Competition link: Come and explore happiness together! Friendly reminder: I just started learning machine learning. Some places may not b ...

Note: This article is part of the understanding ASP.NET Core series. Please check the top blog or Click here to view the full-text catalog Error handling using middleware Developer exception page The developer exception page is used to display the details of unhandled request exceptions. When we create a project through the ASP.NET Core templa ...

1. If there are multiple conditions We can store multiple values in an array and use the array include method. //Longhand if (x === 'abc' || x === 'def' || x === 'ghi' || x ==='jkl') { //logic } //Shorthand if (['abc', 'def', 'ghi', 'jkl'].includes(x)) { //logic } 2. If true... Otherwise abbreviated This is a big shortcut when we have ...

Author: slow timeSource: cnblogs.com/Tom-shushu/p/14279357.html 1, Preface The export and import of Excel and PDF is a problem we often encounter in our work. Just today, the company's business encountered this problem. By the way, take a note to prevent the same problem from being helpless next time. The company has two needs: Requirement ...

This article is for reference only. It is prohibited to use it for any form of commercial use. Violators shall bear their own responsibilities.preparation:(1) , mobile phones (both Android and ios) / Android simulators. Today, Android simulators are mainly used, and the operation process is the same.(2) . packet capture tool: Fiddel download ad ...

File directory operation example 1 - traversal The practical operations available in this example are: making file and directory management program, disk occupancy management, batch copying, moving and compressing files and directories, etc. The basic implementation uses get to recursion and os.walk; The extended implementation will get to ...

 #include<stdio.h> #include<math.h> int main() {  int a, b, c;  float area;  double s;   printf("please enter three sides of the triangle:");  scanf_s("%d,%d,%d", &a, &b, &c);  s = (a + b + c) / 2.0;  if (a + b <= c || b + c <= a || a + c <= b)   printf("does not form a triangle \ n&q ...