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What data types are there in php?

PHP data types include strings, integers, floating point numbers, Boolean values, arrays, objects, and nulls. Detailed introduction: 1. String, a data type composed of a series of characters. Strings can be enclosed in single quotes or double quotes; 2. Integers are numbers without decimal points. Integers in PHP can be positive, negative or Zero; 3. Floating point numbers are numbers with a decimal point. In PHP, floating point numbers can also be expressed in scientific notation; 4. Boolean values, which have only two values, namely true and false; 5. Arrays and so on.

Aug 16, 2023 pm 04:50 PM

php 数据类型

What are the program structures in php

PHP program structures include sequential structure, conditional structure, loop structure, function structure, class and object structure, etc. Detailed introduction: 1. Sequential structure is the most basic program structure. The code is executed in order from top to bottom and is used to execute a series of operations or statements; 2. Conditional structure allows different executions based on the true or false of the condition. For code blocks, PHP provides a variety of conditional structures, including if statements, if-else statements, if-elseif-else statements and switch statements; 3. Loop structures and so on.

Aug 16, 2023 pm 04:17 PM

php 程序结构

What are the default homepages of php?

PHP's default homepage includes index.php, index.html, default.php, home.php, index.cgi, etc. Detailed introduction: 1. index.php, which usually contains the main content and functions of the website, such as navigation bar, article list, login interface, etc.; 2. index.html, when the server cannot find the index.php file, it will continue to search The index.html file serves as the default home page; 3. default.php and so on.

Aug 16, 2023 pm 04:05 PM

php

What are the keywords in php

PHP keywords include echo, if, else, elseif, for, while, do-while, switch, case, default, break, continue, function, return, include, require, class, public, private, protected, etc. Detailed introduction: 1. The echo keyword is used to output text or variable values on the web page; 2. if, else keywords, etc.

Aug 16, 2023 pm 03:48 PM

php 关键字

What are the core technologies of php

PHP core technologies include syntax foundation, functions and classes, database operations, file operations, form processing, security, error handling and debugging, caching technology, extensions and frameworks. Detailed introduction: 1. Syntax basics. Understanding PHP syntax is the basis for using PHP; 2. Functions and classes. PHP provides a large number of built-in functions, which can be used for string processing, file operations, date and time processing, etc.; 3. Database Operation, PHP provides a series of database-related functions and extensions, which can perform database connection, query, insert, update, delete and other operations.

Aug 16, 2023 pm 03:28 PM

php 核心技术

What are the PHP code scanning tools?

PHP code scanning tools include PHP_CodeSniffer, PHPMD, PHPStan, PHPLint, SonarQube, RIPS, Phan, Exakat, etc. Detailed introduction: 1. PHP_CodeSniffer, used to check whether PHP code conforms to consistent coding standards and guidelines; 2. PHPMD, used to discover potential and bad practices in PHP code; 3. PHPStan, used to check PHP code type errors and inconsistencies ; 4. PHPLint and so on.

Aug 16, 2023 pm 03:22 PM

php

What operators are there in php

The operators of PHP are: 1. Arithmetic operators, addition +, subtraction -, multiplication *, division /, remainder %; 2. Assignment operators, addition +=, subtraction -=, multiplication *=, division /=, Remainder %=; 3. Comparison operators, equality ==, congruence ===, inequality!=, incongruence!==, greater than >, less than <, greater than or equal to >=, less than or equal to <=; 4. Logical operators, and && or and, or || or or, not! or not; 5. Bitwise operators, bitwise AND&, bitwise OR|, bitwise XOR^, left shift <<, right shift> >Wait.

Aug 16, 2023 pm 03:17 PM

php 运算符

What are the built-in constants in php?

PHP internal constants include PHP_VERSION, PHP_OS, PHP_EOL, PHP_INT_MAX, PHP_INT_MIN, PHP_INT_SIZE, PHP_ROUND_HALF_UP, PHP_ROUND_HALF_EVEN, PHP_ROUND_HALF, PHP_FLOAT_MAX, PHP_FLOAT_DIG, PHP_BINARY, PHP_SAPI, PHP_SELF, etc.

Aug 16, 2023 pm 03:09 PM

php

What are the simple interest design patterns in PHP?

PHP single-interest design patterns include: 1. Hungry-style singleton mode, which means to create an instance when the class is loaded and then directly return the instance; 2. Lazy-style singleton mode, when the method of obtaining the instance is called for the first time Only create an instance to achieve delayed loading; 3. Double check locking singleton mode, based on the lazy singleton mode, ensures thread safety through locking, achieving delayed loading and thread safety; 4. Using static variables Singleton mode saves the instance in a static variable and provides a static method to obtain the instance to achieve simple thread safety.

Aug 16, 2023 pm 03:04 PM

php 设计模式

What are the php regulators?

PHP regulators include Opcode cache, database connection pool, asynchronous programming, caching system, concurrent processing, security protection, performance analysis tools, coding standards and optimization, etc. Detailed introduction: 1. Opcode cache, a tool that compiles PHP code into machine code and caches it; 2. Database connection pool, the application obtains a database connection from the connection pool when needed, instead of re-establishing the connection every time; 3. Asynchronous programming can convert some time-consuming operations into non-blocking methods, thereby improving the concurrent performance of the program; 4. Cache system, etc.

Aug 16, 2023 pm 02:58 PM

php

What are the magic functions of PHP?

PHP's magic functions include construct(), destruct(), get, set(), isset(), unset(), call(), callStatic(), toString(), invoke(), clone(), sleep() , wakeup(), set_state(), debugInfo(), etc. Detailed introduction: 1. construct(), initialize the properties of the object or perform other necessary operations, etc.

Aug 16, 2023 pm 02:48 PM

php

What are the simple systems in php?

Simple PHP systems include: 1. Blog system, a common Web application, which allows users to publish and manage their own articles; 2. Online mall system, an e-commerce platform, which allows users to display and sell sellers; 3. Social network system, which allows users to publish and manage their own articles. Applications with functions such as creating personal profiles, adding friends, posting status updates, etc.; 4. Online learning platform, a website that provides education and training resources, where users can register, log in, browse courses, and learn courses; 5. Task management system, allowing users to create , applications for assigning and tracking tasks.

Aug 16, 2023 pm 02:15 PM

php

What are the ways to write comments in php

PHP comments are written as follows: 1. Single-line comments, starting with "//", followed by comments, used to explain a specific part of the code; 2. Multi-line comments, starting with "/*", ending with " */" ends, spans multiple lines, and can be used anywhere in the code to explain a piece of code in detail; 3. Document block comments, starting with "/**" and ending with "*/", use Use special tags and syntax to specify the format of the document; 4. Others, such as # are usually used to temporarily block a line of code, //TODO is used to mark to-do items.

Aug 16, 2023 pm 02:03 PM

php 注释

What are the PHP garbage collection projects?

PHP garbage collection projects include: 1. Reference counting, by counting the references to variables, when the count is 0, the variables will be released; 2. Mark clearing, by traversing all reachable objects, marking the referenced objects, and then clearing the unused objects. Mark objects to ensure that memory no longer used is released; 3. Generational recycling, divide objects into different generations. Each generation has its own garbage collection strategy. When the first generation is full, garbage collection will be triggered; 4. Memory pool , divide the memory into fixed-size blocks, each block has a mark indicating whether it is used, and when the object is no longer used, it will be marked as free.

Aug 16, 2023 pm 01:34 PM

php 垃圾回收

What are the php reporting tools?

PHP reporting tools include PHPExcel, FPDF, TCPDF, JpGraph, PHPlot, Google Charts, etc. Detailed introduction: 1. PHPExcel supports multiple file formats, including Excel, CSV and HTML. Using PHPExcel, you can easily generate various complex Excel reports and import and export data; 2. FPDF provides a wealth of Functions, including support for text, images, tables and links; 3. TCPDF tools, etc.

Aug 15, 2023 pm 06:02 PM

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