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    ctype_space

    (PHP 4 >= 4.0.4, PHP 5, PHP 7, PHP 8)

    ctype_space — 检测空白字符

    说明

    ctype_space(mixed $text): bool

    检测提供的 string 类型的 text 里面的所有字符是否都是创建空白。

    参数

    text

    要测试的字符串。

    注意:

    如果给出一个 -128 到 255 之间(含)的int, 将会被解释为该值对应的ASCII字符 (负值将加上 256 以支持扩展ASCII字符). 其它整数将会被解释为该值对应的十进制字符串.

    警告

    自 PHP 8.1.0 起，弃用传递非字符串参数。未来该参数将解释为字符串而不是 ASCII 码点。根据预期行为，应将参数转为字符串或显式调用 chr()。

    返回值

    如果 text 里面的每个字符都创建某种形式的空白，那么就返回 true；否则返回 false。除了空白字符，还包括制表符、垂直制表符、换行符、回车和换页符。当使用空字符串调用时，结果始终为 false。

    示例

    示例 #1 ctype_space() 示例

    <?php
    $strings     = array(
    'string1' => "\n\r\t",
    'string2' => "\narf12",
    'string3' => '\n\r\t' // 注意单引号
    );
    foreach (    $strings as $name => $testcase) {
    if (    ctype_space($testcase)) {
    echo     "The string '$name' consists of whitespace characters only.\n";
    } else {
    echo     "The string '$name' contains non-whitespace characters.\n";
    }
    }
    ?>

    以上示例会输出：

    The string 'string1' consists of whitespace characters only.
The string 'string2' contains non-whitespace characters.
The string 'string3' contains non-whitespace characters.

    参见

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    User Contributed Notes 2 notes

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    7
    gardnerjohng at hotmail dot com
    15 years ago
    A function I wrote last night was fairly flexible in terms of detecting whitespace, and even took into account the pesky non-breaking spaces / zero-width spaces further up the Unicode alphabet.

    The benefit here was being able to isolate and identify specific Unicode indices based on their subrange.

    <?php
            //    Returns TRUE if the ASCII value of $string matches a registered whitespace character.
        //    *    This includes non-breaking spaces, zero-width spaces, and any unicode values below 32.
        //    *    $string: Character to identify. If string extends past one character, the value
        //        is truncated and only the initial character is examined.
            function is_whitespace($string){
                //    Return FALSE if passed an empty string.
                if($string == "") return FALSE;
           
                $char    =    ord($string);
           
                //    Control Characters
                if($char < 33)                        return TRUE;
            if(    $char > 8191 && $char < 8208)    return TRUE;
            if(    $char > 8231 && $char < 8240)    return TRUE;
           
                //    Additional Characters
                switch($char){
                case     160:    // Non-Breaking Space
                    case 8287:    // Medium Mathematical Space
                        return TRUE;
                    break;
            }
            return     FALSE;
        }
    ?>
    up
    1
    vlabots at gmail dot com
    10 years ago
    thanks to gardnerjohng, but a had some problems with non-breaking spaces in this function.

    I added 2 more cases for this:
    case 0xC2
    case 0xA0

    After this modification non-breaking spaces in my test code were successfully detected.
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