ctype_space

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

ctype_space — 做空白字符检测

说明

bool ctype_space ( string $text )

检查提供的 string 和 text 里面的字符是否包含空白。

参数

text

需要被测试的字符串。

返回值

如果 text 里面的每个字符最终被实际输出的时候都是某种形式的空白，就返回 TRUE ；否则返回 FALSE 。 除了空白字符，还包括缩进，垂直制表符，换行符，回车和换页字符。

范例

Example #1 一个 ctype_space() 例子

<?php
$strings = array('string1' => "\n\r\t", 'string2' => "\narf12", 'string3' => '\n\r\t');
foreach ($strings as $name => $testcase) {
    if (ctype_space($testcase)) {
        echo "The string '$name' consists of all whitespace characters.\n";
    } else {
        echo "The string '$name' does not consist of all whitespace characters.\n";
    }
}
?>

以上例程会输出：

The string 'string1' consists of all whitespace characters.
The string 'string2' does not consist of all whitespace characters.
The string 'string3' does not consist of all whitespace characters.

注释

Note:

如果给出一个 -128 到 255 之间(含)的整数, 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.

参见

User Contributed Notes

vlabots at gmail dot com 18-Jun-2014 04:03
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.
gardnerjohng at hotmail dot com 15-Sep-2009 06:00
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;
    }
?>