Detailed explanation of how to use php include-PHP Tutorial-php.cn

Home

Backend Development

PHP Tutorial

Detailed explanation of how to use php include

黄舟

Jun 25, 2017 am 10:42 AM

include php Detailed explanation

include statement includes and runs the specified file.

The following documents also apply to require.

Included filesFirst search according to the path given by the parameter. If no directory (only file name) is given, search according to the directory specified by include_path. If the file is not found under include_path, include will finally search in the directory where the calling script file is located and the current working directory. The include structure will issue a warning if the file is not found at the end; this is different from require, which will issue a fatal error.

If a path is defined - whether it is an absolute path (starting with a drive letter or \ under Windows, and / under Unix/Linux) or a relative path to the current directory (starting with . or ..) --include_path will be completely ignored. For example, if a file begins with ../, the parser will look for the file in the parent directory of the current directory.

For more information on how PHP handles include files and include paths, see the documentation in the include_path section.

When a file is included, the code contained in it inherits the

variable scope of the line where the include is located. From that point on, any variables available in the calling file at that line are also available in the called file. However, all functions and classes defined in include files have global scope.

php include function should be our most commonly used method. The include() statement includes and runs the specified file. But just because of this, we may have overlooked some of its other uses. I read it again because of work needs, and will make a brief record here:

1. The simple difference between include and require

When the file included in include does not exist, it only generates a warning, but the script will continue to execute.

If the file referenced by require does not exist, an error will be prompted and the script will be terminated.

2. Variable scope of variables in the included file

When a file is included, the code contained in it inherits the variable scope of the line where include is located. If include appears within a function in a calling file, all code contained in the called file will behave as if it were defined inside that function. However, all functions and classes defined in include files have global scope.

When a file is included, the parser leaves PHP mode and enters HTML mode at the beginning of the target file, and resumes at the end of the file. For this reason, any code in an object file that should be executed as PHP code must be included within valid PHP start and end tags.

3.include() return value

If you obtain the variable value in include, you need to add return

For example: file return.php

<?php
  $var=&#39;ok&#39;;
  return $var;
?>

Copy after login

if( include('return.php')=='ok' ) { ... } if does not execute the inside because the include('return.php') value is 1

if( (include 'return.php')=='ok' ) { ... } if can execute the

inside, so if you use include for conditional comparison, you need to do this (include 'return.php')

4. Use output buffering to include the PHP file into a

string

<?php
$string = get_include_contents(&#39;somefile.php&#39;);
function get_include_contents($filename) {
    if (is_file($filename)) {
        ob_start();
        include $filename;
        $contents = ob_get_contents();
        ob_end_clean();
        return $contents;
    }
    return false;
}
?>

Copy after login

1. Include some class definition files, function files, This is commonly used;

2. Contain HTML files

include "header.htm";

Copy after login

The header.htm above can be integrated with PHP statements.

Because htm static files can be included, a caching mechanism can be designed. For example, some pages can be divided into several parts. Some parts that are inefficient in reading the database can be cached as HTML and then introduced through include.

3.include files can have returns;

$i = include &#39;abc.php&#39;;

Copy after login

abc.php source code example:

<?php
return "hello world";
?>

Copy after login

Then echo $i; will output hello world.

If abc.php does not return, then echo $i will output the variable range of 1

include

$a="hello world";
include "abc.php";

Copy after login

$a is visible in abc.php;

The variables in abc.php are also visible after include; the usage is very flexible!

The above is the detailed content of Detailed explanation of how to use php include. For more information, please follow other related articles on the PHP Chinese website!

Statement of this Website

The content of this article is voluntarily contributed by netizens, and the copyright belongs to the original author. This site does not assume corresponding legal responsibility. If you find any content suspected of plagiarism or infringement, please contact admin@php.cn

Hot AI Tools

Undresser.AI Undress

AI-powered app for creating realistic nude photos

AI Clothes Remover

Online AI tool for removing clothes from photos.

Undress AI Tool

Undress images for free

Clothoff.io

AI clothes remover

Video Face Swap

Swap faces in any video effortlessly with our completely free AI face swap tool!

Hot Article

Assassin's Creed Shadows: Seashell Riddle Solution

4 weeks ago By DDD

What's New in Windows 11 KB5054979 & How to Fix Update Issues

3 weeks ago By DDD

Where to find the Crane Control Keycard in Atomfall

4 weeks ago By DDD

Roblox: Dead Rails - How To Complete Every Challenge

1 months ago By DDD

Atomfall guide: item locations, quest guides, and tips

1 months ago By DDD

Hot Tools

Notepad++7.3.1

Easy-to-use and free code editor

SublimeText3 Chinese version

Chinese version, very easy to use

Zend Studio 13.0.1

Powerful PHP integrated development environment

Dreamweaver CS6

Visual web development tools

SublimeText3 Mac version

God-level code editing software (SublimeText3)

Hot Topics

Where is the login entrance for gmail email?

7711

Java Tutorial

1640

CakePHP Tutorial

1394

Laravel Tutorial

1288

PHP Tutorial

1232

Related knowledge

PHP 8.4 Installation and Upgrade guide for Ubuntu and Debian Dec 24, 2024 pm 04:42 PM

PHP 8.4 brings several new features, security improvements, and performance improvements with healthy amounts of feature deprecations and removals. This guide explains how to install PHP 8.4 or upgrade to PHP 8.4 on Ubuntu, Debian, or their derivati

7 PHP Functions I Regret I Didn't Know Before Nov 13, 2024 am 09:42 AM

If you are an experienced PHP developer, you might have the feeling that you’ve been there and done that already.You have developed a significant number of applications, debugged millions of lines of code, and tweaked a bunch of scripts to achieve op

How To Set Up Visual Studio Code (VS Code) for PHP Development Dec 20, 2024 am 11:31 AM

Visual Studio Code, also known as VS Code, is a free source code editor — or integrated development environment (IDE) — available for all major operating systems. With a large collection of extensions for many programming languages, VS Code can be c

Explain JSON Web Tokens (JWT) and their use case in PHP APIs. Apr 05, 2025 am 12:04 AM

JWT is an open standard based on JSON, used to securely transmit information between parties, mainly for identity authentication and information exchange. 1. JWT consists of three parts: Header, Payload and Signature. 2. The working principle of JWT includes three steps: generating JWT, verifying JWT and parsing Payload. 3. When using JWT for authentication in PHP, JWT can be generated and verified, and user role and permission information can be included in advanced usage. 4. Common errors include signature verification failure, token expiration, and payload oversized. Debugging skills include using debugging tools and logging. 5. Performance optimization and best practices include using appropriate signature algorithms, setting validity periods reasonably,

PHP Program to Count Vowels in a String Feb 07, 2025 pm 12:12 PM

A string is a sequence of characters, including letters, numbers, and symbols. This tutorial will learn how to calculate the number of vowels in a given string in PHP using different methods. The vowels in English are a, e, i, o, u, and they can be uppercase or lowercase. What is a vowel? Vowels are alphabetic characters that represent a specific pronunciation. There are five vowels in English, including uppercase and lowercase: a, e, i, o, u Example 1 Input: String = "Tutorialspoint" Output: 6 explain The vowels in the string "Tutorialspoint" are u, o, i, a, o, i. There are 6 yuan in total

How do you parse and process HTML/XML in PHP? Feb 07, 2025 am 11:57 AM

This tutorial demonstrates how to efficiently process XML documents using PHP. XML (eXtensible Markup Language) is a versatile text-based markup language designed for both human readability and machine parsing. It's commonly used for data storage an

Explain late static binding in PHP (static::). Apr 03, 2025 am 12:04 AM

Static binding (static::) implements late static binding (LSB) in PHP, allowing calling classes to be referenced in static contexts rather than defining classes. 1) The parsing process is performed at runtime, 2) Look up the call class in the inheritance relationship, 3) It may bring performance overhead.

What are PHP magic methods (__construct, __destruct, __call, __get, __set, etc.) and provide use cases? Apr 03, 2025 am 12:03 AM

What are the magic methods of PHP? PHP's magic methods include: 1.\_\_construct, used to initialize objects; 2.\_\_destruct, used to clean up resources; 3.\_\_call, handle non-existent method calls; 4.\_\_get, implement dynamic attribute access; 5.\_\_set, implement dynamic attribute settings. These methods are automatically called in certain situations, improving code flexibility and efficiency.

See all articles