Correct usage of substr and substring in PHP
Everyone knows that there are functions substr and substring for string interception in js. What about php? PHP does not have a directly available substring function, but there is a substr function.
If you don’t believe it, you can test it yourself. A correct piece of code is given below.
<?$a="me";echo(substr($a,,));//输出me?>下面又给出一段错误的代码<?$a="me";echo(subString($a,,));?> substr() 函数返回字符串的一部分。 substr(string,start,length) string:要截取的字符串
start:
Positive number - starts at the specified position in the string
Negative number - starts at the specified position from the end of the string
0 - starts at the specified position in the string Starts at one character
length:
Optional. Specifies the length of the string to be returned. The default is until the end of the string.
Positive number - Return from the position of the start parameter
Negative number - Return from the end of the string
Detailed explanation of the usage of PHP substr()
Definition and usage
## The #substr() function returns a portion of a string. Using the substr() function to intercept Chinese may cause garbled characters. It is recommended to use the mb_substr() function to intercept Chinese. Syntaxsubstr(string,start,length)
<?php $str = 'hello world!'; echo substr($str, 4); // o world! 左起第4开始向右截取到末尾 echo substr($str, 4, 5); // o wor 左起第4开始向右取5位 echo substr($str, 4, -1); // o world 左起第4与右起第1之间的字符 echo substr($str, -8, 4); // o wo 右起第8开始向右截取4位 echo substr($str, -8,-2); // o worl 右起第8与右起第2之间的字符
Analysis on usage of string interception of substr function in PHP, phpsubstr_PHP tutorial
Analysis of usage of string interception of substr function in PHP , phpsubstr
The method of substr_count() function in PHP to obtain the number of occurrences of a substring
The above is the detailed content of Correct usage of substr and substring in PHP. For more information, please follow other related articles on the PHP Chinese website!

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

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

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

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

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

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,

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

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

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 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.
