The difference between strlen, mb_strlen, substr(), mb_substr() and mb_strcut in php

Home

Backend Development

PHP Tutorial

The difference between strlen, mb_strlen, substr(), mb_substr() and mb_strcut in php_PHP tutorial

WBOYWBOYWBOYWBOYWBOYWBOYWBOYWBOYWBOYWBOYWBOYWBOYWB

Jul 13, 2016 pm 05:00 PM

php strlen substr about the difference article of

The article introduces in detail the differences and usage of strlen, mb_strlen, substr(), mb_substr() and mb_strcut. Students who need to learn can refer to it.

About the use of the string splitting function of mb_*:
Configuration under win
Need to install php_mbstring.dll extension
You need to open php_mbstring.dll in php.ini
The configuration under Linux can be easily searched online

The code is as follows

Copy code

代码如下	复制代码
//测试时文件的编码方式要是UTF8 $str='中文a字1符'; echo strlen($str).' ';//14 echo mb_strlen($str,'utf8').' ';//6 echo mb_strlen($str,'gbk').' ';//8 echo mb_strlen($str,'gb2312').' ';//10 ?>

//The encoding method of the file during testing must be UTF8
$str='Chinese character a';

echo strlen($str).'
';//14

echo mb_strlen($str,'utf8').'
';//6

echo mb_strlen($str,'gbk').'
';//8

echo mb_strlen($str,'gb2312').'
';//10

Result analysis: When calculating strlen, a UTF8 Chinese character is treated as 3 lengths, so the length of "Chinese a character 1 character" is 3*4+2=14. When calculating mb_strlen, the internal code is selected as UTF8, then A Chinese character will be calculated as a length of 1, so the length of "Chinese a character 1 character" is 6

mb_strlen default encoding can be passed

Obtained by mb_internal_encoding().

Using these two functions, you can jointly calculate the occupancy of a mixed Chinese and English string (the occupancy of a Chinese character is 2, and the occupancy of an English character is

1 echo (strlen($str) + mb_strlen($str,'UTF8')) / 2;

PHP’s built-in string length function strlen cannot correctly handle Chinese strings. It only gets the number of bytes occupied by the string. For GB2312 Chinese encoding, the value obtained by strlen is twice the number of Chinese characters, while for UTF-8 encoded Chinese, the difference is three times (under UTF-8 encoding, one Chinese character occupies 3 bytes).

String splitting

The substr() function can split text, but if the text to be split includes Chinese characters, you will often encounter problems. In this case, you can use the mb_substr()/mb_strcut function

代码如下	复制代码
echo mb_substr('这样一来我的字符串就不会有乱码^_^', 0, 7, 'utf-8'); ?>

mb_substr splits characters by words, while mb_strcut splits characters by bytes, but neither will produce half a character.

代码如下	复制代码
echo mb_strcut('这样一来我的字符串就不会有乱码^_^', 0, 7, 'utf-8'); ?>

The substr() function can split text, but if the text to be split includes Chinese characters, you will often encounter problems. In this case, you can use the mb_substr()/mb_strcut function. The usage of mb_substr()/mb_strcut is similar to substr(), except that mb_substr()/mb_strcut needs to add one more parameter at the end to set the encoding of the string. However, most servers do not open php_mbstring.dll. You need to open php_mbstring.dll in php.ini. For example:

The code is as follows	Copy code
echo mb_substr('This way my string will not be garbled^_^', 0, 7, 'utf-8');<🎜> ?>

Output: This way my words

The code is as follows	Copy code
echo mb_strcut('This way my string will not be garbled^_^', 0, 7, 'utf-8');<🎜> ?>

Output: like this
As can be seen from the above example, mb_substr splits characters by words, while mb_strcut splits characters by bytes, but neither of them will produce half a character...

Description of mbstring function:

PHP's mbstring extension module provides multi-byte character processing capabilities. The most commonly used method is to use mbstring to split multi-byte Chinese characters. This can avoid the occurrence of half characters. Since it is an extension of PHP, its The performance is also better than some custom multi-byte segmentation functions.

The mbstring extension provides several functions with similar functions, mb_substr and mb_strcut. See their explanation in the manual.

mb_substr
mb_substr() returns the portion of str specified by the start and length parameters.

mb_substr() performs multi-byte safe substr() operation based on number of characters. Position is sqlserver/42852.htm target=_blank >counted from the beginning of str. First character's position is 0. Second character position is 1 , and so on.

mb_strcut
mb_strcut() returns the portion of str specified by the start and length parameters.

mb_strcut() performs equivalent operation as mb_substr() with different method. If start position is multi-byte character's second byte or larger, it starts from first byte of multi-byte character.

It subtracts string from str that is shorter than length AND character that is not part of multi-byte string or not being middle of shift sequence.

For another example, there is a piece of text that is segmented using mb_substr and mb_strcut respectively:

PLAIN TEXT
CODE:

The code is as follows

代码如下

复制代码

$str = '我是一串比较长的中文-www.webjx.com';

echo "mb_substr:" . mb_substr($str, 0, 6, 'utf-8');

echo "
";

echo "mb_strcut:" . mb_strcut($str, 0, 6, 'utf-8');
?>

Copy code

$str = 'I am a relatively long string of Chinese-www.webjx.com';

echo "mb_substr:" . mb_substr($str, 0, 6, 'utf-8');

代码如下

复制代码

/**
* 字符串分割按字分割
* @param $content string
* @param $length int
* @param $etc string
* @return string
*/
function Truncate($content, $length, $etc = '...') {

if ($length == 0) {
return '';
} elseif (mb_strlen($content,'utf-8') > $length) {
            $length -= min($length, mb_strlen($etc));
            $charset = 'utf-8';
            $content = mb_substr($content, 0, $length, $charset) . $etc;
        }
        return $content;
    }

$str ='伏尔泰（1694～1778）法国资产阶级启蒙思想家，哲学家，史学家，文学家。伏尔泰原名F.M.阿鲁埃。';

echo strlen($str);//字符串长度
echo '

';
echo mb_strlen($str,'utf-8');//字符串长度
echo '

';
echo mb_strcut($str,0,35,'utf-8');//按字节分割
echo '

';
echo mb_substr($str,0,35,'utf-8');//按字分割
echo '

';
echo Truncate($str,35);//字符串截取方法

echo "
"; echo "mb_strcut:" . mb_strcut($str, 0, 6, 'utf-8'); ?> The output results are as follows: mb_substr: I am a string of comparisons mb_strcut:I am Test code:

The code is as follows

Copy code

/** * String splitting by word * @param $content string * @param $length int * @param $etc string * @return string */ function Truncate($content, $length, $etc = '...') { if ($length == 0) { return ''; } elseif (mb_strlen($content,'utf-8') > $length) { $length -= min($length, mb_strlen($etc)); $charset = 'utf-8'; $content = mb_substr($content, 0, $length, $charset) . $etc; } return $content; } $str ='Voltaire (1694～1778) French bourgeois Enlightenment thinker, philosopher, historian, and writer. Voltaire's original name was F.M. Arrouet. '; echo strlen($str);//String length echo '

'; Echo mb_strlen($str,'utf-8');//String length echo '

'; echo mb_strcut($str,0,35,'utf-8');//Split by bytes echo '

'; echo mb_substr($str,0,35,'utf-8');//Split by word echo '

'; echo Truncate($str,35);//String interception method

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

1 months 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

1 months ago By DDD

How to fix KB5055523 fails to install in Windows 11?

2 weeks ago By DDD

InZoi: How To Apply To School And University

3 weeks 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?

7750

Java Tutorial

1643

CakePHP Tutorial

1397

Laravel Tutorial

1293

PHP Tutorial

1234

Related knowledge

PHP and Python: Comparing Two Popular Programming Languages Apr 14, 2025 am 12:13 AM

PHP and Python each have their own advantages, and choose according to project requirements. 1.PHP is suitable for web development, especially for rapid development and maintenance of websites. 2. Python is suitable for data science, machine learning and artificial intelligence, with concise syntax and suitable for beginners.

PHP: A Key Language for Web Development Apr 13, 2025 am 12:08 AM

PHP is a scripting language widely used on the server side, especially suitable for web development. 1.PHP can embed HTML, process HTTP requests and responses, and supports a variety of databases. 2.PHP is used to generate dynamic web content, process form data, access databases, etc., with strong community support and open source resources. 3. PHP is an interpreted language, and the execution process includes lexical analysis, grammatical analysis, compilation and execution. 4.PHP can be combined with MySQL for advanced applications such as user registration systems. 5. When debugging PHP, you can use functions such as error_reporting() and var_dump(). 6. Optimize PHP code to use caching mechanisms, optimize database queries and use built-in functions. 7

The Future of PHP: Adaptations and Innovations Apr 11, 2025 am 12:01 AM

The future of PHP will be achieved by adapting to new technology trends and introducing innovative features: 1) Adapting to cloud computing, containerization and microservice architectures, supporting Docker and Kubernetes; 2) introducing JIT compilers and enumeration types to improve performance and data processing efficiency; 3) Continuously optimize performance and promote best practices.

PHP vs. Python: Understanding the Differences Apr 11, 2025 am 12:15 AM

PHP and Python each have their own advantages, and the choice should be based on project requirements. 1.PHP is suitable for web development, with simple syntax and high execution efficiency. 2. Python is suitable for data science and machine learning, with concise syntax and rich libraries.

PHP's Current Status: A Look at Web Development Trends Apr 13, 2025 am 12:20 AM

PHP remains important in modern web development, especially in content management and e-commerce platforms. 1) PHP has a rich ecosystem and strong framework support, such as Laravel and Symfony. 2) Performance optimization can be achieved through OPcache and Nginx. 3) PHP8.0 introduces JIT compiler to improve performance. 4) Cloud-native applications are deployed through Docker and Kubernetes to improve flexibility and scalability.

PHP's Purpose: Building Dynamic Websites Apr 15, 2025 am 12:18 AM

PHP is used to build dynamic websites, and its core functions include: 1. Generate dynamic content and generate web pages in real time by connecting with the database; 2. Process user interaction and form submissions, verify inputs and respond to operations; 3. Manage sessions and user authentication to provide a personalized experience; 4. Optimize performance and follow best practices to improve website efficiency and security.

PHP vs. Other Languages: A Comparison Apr 13, 2025 am 12:19 AM

PHP is suitable for web development, especially in rapid development and processing dynamic content, but is not good at data science and enterprise-level applications. Compared with Python, PHP has more advantages in web development, but is not as good as Python in the field of data science; compared with Java, PHP performs worse in enterprise-level applications, but is more flexible in web development; compared with JavaScript, PHP is more concise in back-end development, but is not as good as JavaScript in front-end development.

The Enduring Relevance of PHP: Is It Still Alive? Apr 14, 2025 am 12:12 AM

PHP is still dynamic and still occupies an important position in the field of modern programming. 1) PHP's simplicity and powerful community support make it widely used in web development; 2) Its flexibility and stability make it outstanding in handling web forms, database operations and file processing; 3) PHP is constantly evolving and optimizing, suitable for beginners and experienced developers.

See all articles