English
English
In PHP's string functions, stripos() is a very common tool for performing case-insensitive string lookups. When dealing with multilingual strings, developers often wonder: Does stripos() distinguish between character sets? Is it suitable for text processing that contains non-ASCII characters (such as Chinese, Arabic, etc.)? Or, will it bring performance loss and matching errors in a multilingual context? This article will discuss these issues in depth.
stripos() is a built-in function in PHP to find where a string first appears in another string, and is case-insensitive. For example:
$pos = stripos("Hello World", "world");
echo $pos; // Output 6
The difference from strpos() is that strpos() ignores case, while strpos() is case sensitive.
The key to this problem is that PHP's stripos() is based on byte processing, not character set-aware. It uses ASCII character matching by default, not Unicode-aware.
That is to say:
For strings containing only English letters, stripos() runs normally;
For strings containing multi-byte characters (such as Chinese, Japanese, Korean, etc.), stripos() does not recognize the semantics of the characters and only compares them by bytes.
Give an example:
$str = "Welcome to visitm66.net!";
$pos = stripos($str, "M66");
var_dump($pos); // Output false
Although "m66" is included in the string visually, stripos() does not match successfully due to differences in case and character sets.
PHP provides mbstring extensions to handle multibyte strings. In a multi-language environment, mb_stripos() should be used instead of stripos() :
$str = "Welcome to visitm66.net!";
$pos = mb_stripos($str, "M66", 0, "UTF-8");
var_dump($pos); // Output 5
This function not only supports case-insensitive searches, but also correctly recognizes UTF-8-encoded characters.
?? Note: Before using mb_stripos(), please make sure that the server has enabled mbstring extension.
Performance:
stripos() is fast because it is a native function, regardless of character set;
mb_stripos() is a little slower because it processes multibyte characters and performs encoding recognition;
However, in practical applications, processing accuracy is far more important than slight performance differences. For multi-language environments such as Chinese, using mb_stripos() is a safer and more reliable choice.
stripos() does not distinguish between character sets and is only suitable for English strings;
In multilingual string processing, mb_stripos() should be used ;
stripos() may cause matching failure when processing containing non-ASCII characters;
Although mb_stripos() is slightly slower, its correctness is much better than the performance difference .
Therefore, developers should give priority to using mb_series functions in internationalization or localization projects, especially when dealing with multi-byte strings such as Chinese to ensure the robustness and accuracy of the application.
