Found a total of 10000 related content
A complete collection of commonly used basic commands for CentOS
Article Introduction:This article provides a guide to essential CentOS commands. It covers file management (ls, cd, mkdir, rm, cp, mv, touch, cat, less, head, tail, find), system information (uname, df, du, top, ps, kill), and basic network troubleshooting (ping, netsta
2025-03-05
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469
How to Create JSON Arrays in PHP?
Article Introduction:JSON Array Creation in PHPIn PHP, JSON (JavaScript Object Notation) arrays are commonly used to store a collection of key-value pairs. To create a...
2024-12-15
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875
What are Java Collections framework key interfaces?
Article Introduction:The Java Collection Framework core includes 5 key interfaces. 1.Collection is the root interface, which defines basic operations such as addition, deletion, and traversal; 2. List is an ordered repeatable collection, and commonly used implementations include ArrayList and LinkedList; 3.Set is a collection of repetitive elements, and is commonly implemented as HashSet, LinkedHashSet and TreeSet; 4. Map handles key-value pairs, and the main implementation classes include HashMap, LinkedHashMap and TreeMap; 5. Iterator is used to safely traverse collection elements and supports flexible control of the traversal process. These interfaces and their implementations constitute the core system for Java data collection processing.
2025-07-17
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699
How to manipulate the DOM with js?
Article Introduction:Operating DOM is the foundation of front-end development, and mastering its core methods and precautions is the key to achieving web page interaction. When getting elements, document.getElementById(), document.querySelector() and document.querySelectorAll() are commonly used. The first two are used to obtain a single element through ID and obtain the first matching element through CSS selector respectively, while querySelectorAll returns a static NodeList; note that getElementsByClassName and getElementsByTagName return a dynamic collection. Modify content and
2025-06-27
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1027
How to use std::map and std::set in the C STL?
Article Introduction:std::map and std::set are commonly used associative containers in C STL, which are used to store key-value pairs and unique element sets, respectively. 1.std::map quickly retrieves values ??through keys, and defaults to sort by key, and supports insert, [], at, find and other operations; 2.std::set is used to maintain a unique and ordered collection of elements, and is commonly used to operate with insert, erase, and find; 3. When using it, be careful to avoid misuse of [] and cause default insertion. Priority is given to using find to check existence. Unordered versions can be used to improve performance when sorting is not required. Both provide O(logn) time complexity search, insert, and delete operations.
2025-06-27
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945
Useful CSS Selectors You Might Not Know
Article Introduction:CSS selectors play a vital role in web development and are used for web page styling. While many people are familiar with common selectors, there are some less common but very useful selectors. What are CSS selectors? CSS selectors are patterns used to select elements on a web page for styling. They can locate elements based on attributes, classes, IDs, etc. Commonly used CSS selectors The following are some commonly used selectors: Element selector: locates all elements of a specific type. For example, to style all elements: div{border:1pxsolidblack;} Class Selector: Selects elements with a specific class. If we have a class called "text-large"
2025-01-14
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798
I Finally Found the Perfect Alternative to MAMP
Article Introduction:For web developers using macOS, MAMP is a commonly used software that allows for quick and easy setup of a development environment with just one click. However, MAMP is not without its limitations, especially the free version, which restricts many fe
2025-01-03
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1013
Using Predicates and Consumers in Java 8 Functional Programming
Article Introduction:In Java8, Predicate is used for conditional judgment, accepting parameters and returning boolean values, which are often used to filter data, such as filtering elements that meet the conditions in combination with filter() method; it can encapsulate complex logic and support combination operations of and(), or(), and negate(). Consumer is used to perform operations without return values. It is commonly used when forEach traversing the collection, such as printing or logging; it supports multiple operations in sequence through andThen() chain call. It should avoid too many side effects when using it. It is recommended to use references to improve the simplicity of the code and combine it with StreamAPI to play a greater role.
2025-07-08
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953
How to start HTML for beginners?
Article Introduction:The steps to learn HTML include: 1. Understand the basic concepts and structure of HTML; 2. Write a simple HTML page; 3. Master commonly used HTML tags and attributes; 4. Know how to view and debug web pages in the browser. HTML is the foundation of front-end development. By learning these steps, you can start from scratch and gradually master web design skills.
2025-04-03
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1170
Understanding Java Race Conditions and Solutions
Article Introduction:The race condition is the data inconsistency problem caused by unorderly accessing shared resources between threads in a multi-threaded environment. 1. It may occur when multiple threads read and write the same variable at the same time and at least one thread modifies data; 2. Commonly used in non-thread-safe collection classes, singleton state modifications and other scenarios; 3. It can be identified through unstable results, tool detection, and outlier judgments; 4. Solutions include the use of synchronized, Lock interfaces, atomic classes, and thread-safe collections, while volatile is used to ensure visibility but cannot prevent all competition situations.
2025-07-16
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779
Getting Started with Flask, a Python Microframework
Article Introduction:This article introduces Flask, a popular Python mini framework that provides an alternative to the vast Django framework.
Flask's design philosophy is lightweight and flexible, allowing developers to quickly and easily create web applications. This article will cover what Flask is, its key features, the advantages of a simple API, its flexibility in supporting third-party extensions, the most commonly used Flask extensions, and when Flask should or should not be used.
Important points
Overview of Flask Features and Use Cases: This article introduces Flask, focusing on its lightweight, flexible features and its applicability to a variety of web projects. It explores Flask's simplicity, extended support, key features, and prototype design
2025-02-16
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674
Introducing STRICH: Barcode Scanning for Web Apps
Article Introduction:Efficient and convenient web barcode scanning: Use STRICH library to build web applications
This article will introduce how to use the STRICH JavaScript library to implement real-time one-dimensional/two-dimensional barcode scanning function in web applications, and explain the advantages of barcode scanning of web applications over native applications.
Core advantages of STRICH library:
Real-time scanning: The STRICH library supports all commonly used one-dimensional and two-dimensional barcode types and uses WebGL and WebAssembly technologies to achieve efficient and reliable scanning.
Simplified development: Just develop for a single platform (Web browser), simplifying the development process and reducing development costs.
Easy deployment: no App Store review required, department
2025-02-08
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1284
PHP vs. Python: Use Cases and Applications
Article Introduction:PHP is suitable for web development and content management systems, and Python is suitable for data science, machine learning and automation scripts. 1.PHP performs well in building fast and scalable websites and applications and is commonly used in CMS such as WordPress. 2. Python has performed outstandingly in the fields of data science and machine learning, with rich libraries such as NumPy and TensorFlow.
2025-04-17
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1079
Teaching data structures in JavaScript online practice
Article Introduction:In computer science, a data structure is a way of organizing, managing, and storing data so that it can be accessed and modified efficiently.
A data structure contains a set of values, the relationships between them, and the operations or functions that can be performed on them. For example, an array is a data structure that can store a list of values, maintain their order, and have functions and methods for adding or removing values ??from the list.
Next, we’ll explore the most commonly used data structures in JavaScript:
Indexed Collections
An indexed collection is a set of data sorted numerically (indexed). Indexed collections in JavaScript include arrays and array-like structures, which we discuss below:
Array
2025-01-18
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539