How to use PHP's MBstring extension?

PHP is a popular programming language that is widely used in web development, server-side scripting, command line scripting and other fields. Among them, string operation is a commonly used function in PHP programming. In order to operate multi-byte characters, PHP provides an extension called MBstring. This article will introduce how to use PHP's MBstring extension.

1. Introduction to MBstring extension

MBstring extension is a PHP extension used to operate multi-byte characters. Its main function is to provide a set of string processing that implements Unicode character encoding. function. For web application development with non-English character sets, using the MBstring extension can greatly simplify development work.

2. Installation of MBstring extension

The MBstring extension is a built-in extension of PHP, so it is already included in the PHP installation. However, to enable the MBstring extension in PHP, you need to add the following code to the php.ini configuration file:

extension=php_mbstring.dll

If you are using a Linux system, you can add the following code to the php.ini configuration file:

extension=mbstring.so

After completing the configuration, restart the web server to take effect.

3. Use of MBstring extension

The function using MBstring extension needs to pass in a string encoding parameter to specify the encoding type of the string. Common encoding types include UTF-8, GBK, BIG5 and other encoding methods.

1. mb_strlen() function

The mb_strlen() function is used to obtain the length of a string, but it is different from the strlen() function that comes with PHP. The mb_strlen() function Can handle multi-byte characters such as Chinese. The following is how to use the mb_strlen() function:

$str = "PHP中文网";
echo mb_strlen($str, 'UTF-8');  // 输出： 6

2. mb_substr() function

mb_substr() function is used to obtain the string of a string, and can also handle multiple Byte characters. The following is how to use the mb_substr() function:

$str = "PHP中文网";
echo mb_substr($str, 3, 2, 'UTF-8');  // 输出：中文

3. mb_strpos() function and mb_strrpos() function

mb_strpos() function and mb_strrpos() function are used for search The position of the first or last occurrence of a character in a string. Multi-byte characters can also be processed. The following is how to use the mb_strpos() function and mb_strrpos() function:

$str = "PHP中文网";
echo mb_strpos($str, "中", 0, 'UTF-8');  // 输出： 3
echo mb_strrpos($str, "中", 0, 'UTF-8'); // 输出： 3

4. Precautions for MBstring expansion

1. When the MBstring expansion function operates multi-byte characters, The correct character encoding type must be specified, otherwise garbled or incorrect results will occur.
2. If you want to process multi-byte characters such as Chinese in PHP, it is recommended to use the functions in the MBstring extension.
3. After PHP version 7.2, the MBstring extension was included in the official abandoned extension list. It is recommended to use other extensions, such as Iconv, Intl, etc.

Summary:

This article introduces how to install and use the MBstring extension of PHP. In actual development, if you need to process multi-byte characters such as Chinese, you can use the MBstring extension. function to improve the readability and ease of use of the code. However, it should be noted that after PHP7.2, the MBstring extension has been included in the abandoned extension list, and it is recommended to use other extensions.

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