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PHP's mbstring extension provides strong support when dealing with multi-byte characters (such as Chinese, Japanese, and Korean). Especially when we want to intercept strings safely, mb_substr is an indispensable tool. But in actual use, many people ignore the importance of mb_get_info , which can help us understand the current multibyte settings dynamically, thereby avoiding encoding errors.
This article will explain in detail how to use mb_get_info with mb_substr to ensure that your multibyte string operation is both accurate and reliable.
mb_get_info returns detailed information about the current settings of mbstring , such as internal encoding ( internal_encoding ). If we use mb_substr directly without confirming the encoding, garbled code may occur in different environments. Therefore, it is a good habit to understand the current environment configuration in advance.
Example:
<?php
// GetmbstringConfiguration information
$info = mb_get_info();
print_r($info);
// Output e.g.:
// Array
// (
// [internal_encoding] => UTF-8
// [http_output] => UTF-8
// [http_input] => pass
// ...
// )
?>
By looking at internal_encoding , we can know what the encoding is used by default for the current string processing.
mb_substr is specially designed for multi-byte strings. Its basic usage is as follows:
<?php
$string = "Hello，world！";
$substring = mb_substr($string, 0, 2); // From0Start with characters，Pick2Characters
echo $substring; // Output：Hello
?>
If you do not use mb_substr but use ordinary substr , the characters may be truncated because Chinese occupies multiple bytes.
A good practice is: confirm and set the correct encoding before executing mb_substr .
for example:
<?php
// Ensure environmental supportUTF-8
$info = mb_get_info();
if (strtoupper($info['internal_encoding']) !== 'UTF-8') {
mb_internal_encoding('UTF-8');
}
// Use safely nowmb_substr
$string = "Welcome to visit https://gitbox.net/page";
$substring = mb_substr($string, 0, 6); // Pick前6Characters
echo $substring; // Output：Welcome to visit
?>
In this way, even if the server's default encoding is not UTF-8, we can ensure that the program will not make any errors when processing multibyte strings.
In a production environment, it is best to add a simple check to ensure that the mbstring extension is installed and enabled:
<?php
if (!function_exists('mb_substr')) {
die('Please install it firstmbstringExtended！');
}
?>
Otherwise, the program may crash directly in an environment where multi-byte operation is not supported.
mb_get_info helps you understand environment coding and avoid blind operations.
mb_substr is the preferred method for handling multibyte string interception.
Before formally intercepting the string, it is best to confirm and set the encoding, such as unified as UTF-8.
Pay attention to environment compatibility and check whether the mbstring extension is enabled.
After mastering these details, you will no longer have a headache when dealing with Chinese, Japanese, and Korean strings!
