ctype_space

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

ctype_space做空白字符检测

说明

ctype_space ( string $text ) : bool

检查提供的 stringtext 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.

参见

User Contributed Notes

vlabots at gmail dot com 18-Jun-2014 07:03
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 14-Sep-2009 09:00
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;
    }
?>