mb_substr is the correct choice to avoid garbled code when dealing with multibyte characters such as Chinese. 1. It intercepts by characters rather than bytes to ensure that Unicode characters such as Chinese characters are not split; 2. It is recommended to clearly specify the encoding as UTF-8 when using it to avoid system differences; 3. It can combine functions such as mb_strlen and mb_strpos to achieve more reliable string operations; 4. Older versions of PHP need to enable mbstring extension, otherwise it may not work properly.
mb_substr is a very useful function in PHP when processing multi-byte strings (such as Unicode characters such as Chinese and Japanese). It is similar to ordinary substr , but it can correctly handle non-ASCII characters to avoid garbled code.
Basic usage
The syntax of mb_substr is as follows:
mb_substr(string $string, int $start, ?int $length = null, ?string $encoding = null): string
Parameter description:
-
$string: The original string to be intercepted -
$start: Start position (start from 0) -
$length: Intercept the length (optional) -
$encoding: character encoding (usually set to'UTF-8')
A simple example:
$str = "Hello, world!"; echo mb_substr($str, 0, 4, 'UTF-8'); // Output "Hello, World"
Note: "4" here refers to 4 characters, not bytes.
Intercept Chinese strings without garbled code
When dealing with multi-byte characters such as Chinese, using ordinary substr may split a Chinese character in half, resulting in garbled output. For example:
$str = "Chinese test"; echo substr($str, 0, 5); // It may output garbled code, such as "Chinese test"
And there will be no errors when using mb_substr :
echo mb_substr($str, 0, 2, 'UTF-8'); // Output "Chinese"
suggestion:
- When processing non-English content, use
mb_substris preferred - Try to write
'UTF-8'when specifying the encoding to avoid problems caused by different default encodings in the system.
Use in combination with other mb string functions
PHP provides a complete set of mb series functions, such as mb_strlen , mb_strpos , mb_strtolower , etc., which are more effective in combination.
For example, you want to get the first 10 characters of a Chinese text:
$text = "This is a sample text used to test mb_substr.";
$len = mb_strlen($text, 'UTF-8'); // Get the real number of characters if ($len > 10) {
echo mb_substr($text, 0, 10, 'UTF-8') . '...'; // Output the first 10 characters with ellipsis}This ensures that the input can be correctly truncated regardless of whether it is a Chinese-English mixture or pure Chinese.
Things to note
- If no encoding is specified,
mb_substrwill use internal encoding, which may not be the result you want. - In some older versions of PHP, the mbstring extension is not enabled by default and needs to be enabled manually.
- If
$lengthexceeds the remaining characters,mb_substrwill automatically cut to the end and will not report an error.
Basically that's it. The key to using mb_substr is to understand that it operates by characters rather than bytes, which is particularly suitable for handling multilingual content.
The above is the detailed content of PHP mb_substr example. For more information, please follow other related articles on the PHP Chinese website!
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