Advanced PHP programming: How to process Chinese strings without using mb_substr()

Advanced PHP programming: How to process Chinese strings without using mb_substr()

In PHP programming, mb_substr() is often used when processing Chinese strings Function to intercept a string of specified length, especially in projects involving Chinese. However, sometimes we may need to process Chinese strings without using mb_substr(), and in this case we need to use other methods to achieve the same function. This article will introduce some methods to process Chinese strings without using the mb_substr() function, and give specific code examples.

1. Use regular expressions to intercept Chinese strings

Regular expressions are a powerful tool for processing strings and can flexibly match various text patterns. We can use regular expressions to intercept Chinese strings. The following is an example:

function chinese_substr($str, $start, $length) {
    preg_match_all("/./us", $str, $matches);
    $chars = array_slice($matches[0], $start, $length);
    return implode("", $chars);
}

$str = "I love programming, PHP programming is fun!";
$start = 3;
$length = 5;
echo chinese_substr($str, $start, $length); // Output: Programming is fun

In the above code, we use the preg_match_all() function and the regular expression "/./us" to match Chinese characters , and then intercept the Chinese string of the specified length through the array_slice() function and implode() function.

2. Use Unicode encoding to intercept Chinese strings

Another method is to process Chinese strings through Unicode encoding. Each Chinese character occupies 3 bytes in Unicode encoding. We can use this feature to intercept Chinese strings. The following is an example:

function unicode_substr($str, $start, $length) {
    $result = '';
    $strlen = strlen($str);
    $n = 0;
    for($i = 0; $i < $strlen; $i ) {
        if (ord(substr($str, $i, 1)) < 128) {
            $result .= substr($str, $i, 1);
            $n;
        } else {
            $result .= substr($str, $i, 3);
            $i = 2;
            $n;
        }
        if ($n >= $length) {
            break;
        }
    }
    return $result;
}

$str = "I love programming, PHP programming is fun!";
$start = 3;
$length = 5;
echo unicode_substr($str, $start, $length); // Output: Programming is fun

In the above code, we use the ord() function to determine whether the character is an ASCII character. If it is not an ASCII character, then Represented as Chinese characters, 3 bytes are directly taken as one character. Control the truncation length by counting n.

Through the above two methods, we can realize the interception function of processing Chinese strings without using the mb_substr() function. Through the flexible use of regular expressions and Unicode encoding, we can better handle Chinese strings and improve our programming level. I hope this article can help readers in need and make them more comfortable in PHP programming.

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