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catalogue Common libraries for data analysis: 1.Numpy: basic knowledge 1.1 Numpy built-in method for creating multidimensional array 1.2 index of multidimensional array 1.2.1 intercepting elements in the list 1.2.2} array index 1.2.3 ， from 2D to 3D 1.3 basic operation of multidimensional array 1.3.1 addition, subtraction, multiplic ...

1, Explicit and implicit waiting: 1. Direct wait: Forced wait, the thread sleeps for a period of time time.sleep(3) 2. Implicit wait: Set a waiting time, and poll to find out whether the element appears (0.5 seconds by default). If the element appears within the waiting time, exit the waiting. If it does not appear, throw an exception se ...

The string splicing methods discussed in this paper are as follows: "+" sign, StringBuilder, StringJoiner and String#join, which are compared and analyzed to explore the best practices.conclusionThe following content is boring, so let's start with the conclusion:The string splicing methods discussed in this paper are as follows: &quot ...

Basic use of synchronized Object lock Custom object lock /** * Object lock example 2 */ public class SyncObjLock2 implements Runnable{ private static SyncObjLock2 instance=new SyncObjLock2(); private Object lock1=new Object(); private Object lock2=new Object(); /** * You can see that using sync will cause threads to ...

Chapter 7 - thread pool of shared model Thread pool (key) There are many pooling technologies, such as thread pool, database connection pool, HTTP connection pool and so on. The idea of pooling technology is mainly to reduce the consumption of resources and improve the utilization of resources. Thread pools provide a way to limit and ma ...

○ reference links 🔗 Product manual (zabbix.com) Zabbix Chinese document Windows agent installation from MSI 1, Introduction to Zabbix 🔊 🏆 Zabbix is an enterprise class open source solution that provides distributed system monitoring and network monitoring functions based on WEB interface. 🌈 It can monitor various network ...

Design mode_ 03 six design principles Opening and closing principle It is open to extensions and closed to modifications. Implemented through interfaces and abstract classes. Code implementation: class Abstract_father { public: virtual void func() = 0; }; class son1 : Abstract_father { public: void func() { cout << "son1" < ...

Depth first search application Example 1: alphabetical arrangement (subject library 2698) Given a string composed of different lowercase letters, output all the full permutations of the string. Let's assume 'a' < 'B' <... < 'for lowercase letters Y '<' Z ', and the letters in the given string have been arranged from small to large ...

1. Fast power algorithm template Find mk%p, time complexity O(logk). int qmi(int m, int k, int p) { int res = 1 % p, t = m; while (k) { if (k&1) res = res * t % p; t = t * t % p; k >>= 1; } return res; }   2. Binary search algorithm template There are two bisection templates, which are ...

What is dynamic and static separation 1. Dynamic static separation is to separate dynamic resources (jsp/ftl) from static resources (img/css/js), so as to improve the response speed of the website. 2. In the traditional architecture mode, static resources (js, css, img) and dynamic resources (jsp, ftl) are stored on the same server. tomcat its ...