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xlrd xlrd is a third-party module used to read excle tables in python. Many enterprises use tables to manage data before using computer management, so importing tables is very common! Install xlrd pip install xlrd Analysis of excel structure An excle table contains multiple sheet s A sheet contains multiple rows and columns E ...

Qt Quick module is a standard library for writing QML applications. While the Qt QML module provides the QML engine and language infrastructure, the Qt Quick module provides all the basic types needed to create a user interface using QML. It provides a visual canvas, including types for creating and animating visual components, receiving user i ...

The article was forwarded from the professional Laravel developer community. Original link: https://learnku.com/laravel/t... this StackOverflow answer It perfectly explains the concept of dependency injection. Fundamentally speaking, dependency injection is not to let an object create a dependency, nor let a factory object create an object, b ...

Very efficient recursion /** * Definition for a binary tree node. * public class TreeNode { * int val; * TreeNode left; * TreeNode right; * TreeNode(int x) { val = x; } * } */ class Solution { public List<Integer> preorderTraversal(TreeNode root) { List<Integer> ls = new LinkedList<Integer&g ...

14. iterator and for...of loop *Different data structures achieve the goal of reading different data structures through the unified form of for... *But the iterator interface behind it is different. iterator { //Circular array let arr = ["hello", "world"]; let map = arr[Symbol.iterator](); console.log(map.next()); //{v ...

1. Create a new springboot project and add a maven dependency <dependency> <groupId>org.springframework.boot</groupId> <artifactId>spring-boot-starter-websocket</artifactId> </dependency> The file directory structure is as follows: 2. Create websocket server c ...

In this case, you want to customize the level output of the logs in the class or package. Method 1 1. The user-defined log level is as follows: Code file: Logger monitorLogger = LoggerFactory.getLogger("monitor"); / / create a custom level label when declaring an instance. Monitor is the custom label. 2. Output logs in this way: ...

2. Pygal draws stacked histogram, stacked line chart, point chart and pie chart 1) overlay The second group of data in the stack chart will be superimposed on the first group of data, and the accumulation effect of the two groups of data can be seen. The same can be seen for other groups of data. ...

Linux operation and Maintenance Notes (7): smooth upgrade of nginx and 4-tier agent nginx smooth upgrade With the increasing number of concurrent visits to websites, nginx web servers are becoming more and more popular. The version of nginx is changing more and more frequently. The new version of ng ...

Title Description: https://www.luogu.org/problemnew/show/P3391   Analysis: Here we mainly talk about the view of the weights of the points on the splay. First of all, we find that the middle order traversal of a splay is always the same, so we think of using the middle order traversal of a splay to represent the position of the original array ...