ctype_space()

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

做空白字符检测

说明

ctype_space(string $text): bool

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

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

• ctype_cntrl()做控制字符检测
• ctype_graph()做可打印字符串检测，空格除外
• ctype_punct()检测可打印的字符是不是不包含空白、数字和字母

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;
  }
?>

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.