preg_filter

(PHP 5 >= 5.3.0, PHP 7, PHP 8)

preg_filter — 执行一个正则表达式搜索和替换

说明

preg_filter(
    mixed $pattern,
    mixed $replacement,
    mixed $subject,
    int $limit = -1,
    int &$count = ?
): mixed

preg_filter()等价于preg_replace() 除了它仅仅返回(可能经过转化)与目标匹配的结果. 这个函数怎样工作的更详细信息请阅读 preg_replace()文档.

返回值

如果subject是一个数组，返回一个数组，其他情况返回一个字符串。

如果没有找到匹配或者发生了错误，当subject是数组时返回一个空数组，其他情况返回null。

范例

示例 #1 比较preg_filter() 和preg_replace()的示例


<?php
$subject = array('1', 'a', '2', 'b', '3', 'A', 'B', '4'); 
$pattern = array('/\d/', '/[a-z]/', '/[1a]/'); 
$replace = array('A:$0', 'B:$0', 'C:$0'); 

echo "preg_filter returns\n";
print_r(preg_filter($pattern, $replace, $subject)); 

echo "preg_replace returns\n";
print_r(preg_replace($pattern, $replace, $subject)); 
?>

以上例程会输出：

preg_filter returns
Array
(
    [0] => A:C:1
    [1] => B:C:a
    [2] => A:2
    [3] => B:b
    [4] => A:3
    [7] => A:4
)
preg_replace returns
Array
(
    [0] => A:C:1
    [1] => B:C:a
    [2] => A:2
    [3] => B:b
    [4] => A:3
    [5] => A
    [6] => B
    [7] => A:4
)

参见

PCRE 模式
preg_quote() - 转义正则表达式字符
preg_replace() - 执行一个正则表达式的搜索和替换
preg_replace_callback() - 执行一个正则表达式搜索并且使用一个回调进行替换
preg_grep() - 返回匹配模式的数组条目
preg_last_error() - 返回最后一个PCRE正则执行产生的错误代码

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User Contributed Notes 6 notes

down

forsoap at gmail dot com ¶

5 years ago


For those who read manual not in English and figure out that example code returns not the same result as in documentation

You need put in example patter modifier "u" to get same result:

<?php
$subject = array('1', 'а', '2', 'б', '3', 'А', 'Б', '4');
// Added "u"
$pattern = array('/\d/u', '/[а-я]/u', '/[1а]/u');
$replace = array('А:$0', 'Б:$0', 'В:$0');
?>

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bienvenunet at yahoo dot com ¶

4 years ago


If you don't want to actually replace the matches, just filter the array to them, make the replacement parameter '$0'.

<?php
$subject = array('1', 'a', '2', 'b', '3', 'A', 'B', '4'); 
$result = preg_filter('/\d/', '$0', $subject);  // ['1','2','3','4']
?>

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sajina_99 at hotmail dot de ¶

10 years ago


As I had to work with PHP5.2.X and needed preg_filter I wrote a quick and dirty workaround.

<?php
  if (!function_exists('preg_filter')) {
  
    function preg_filter($pattern, $replace, $subject, $limit = -1 , &$count = null) {
    
      if(!is_array($subject)) {
        $noArray = 1 ;
        $subject = array($subject);
      }

      $preg = preg_replace($pattern, $replace, $subject, $limit,  &$count);

      $diff = array_diff($preg, $subject);
      
      if($noArray == 1) $diff = implode($diff) ;

      return $diff ;
      
    }
    
  }
?>

down

-26

MrBertie ¶

11 years ago


Another way to filter an array, and simply return the matching items: preg_grep!

down

-25

fgmhhfg at gmail dot com ¶

8 years ago


As for the php 5.5.3 version, the example  turn out like:
Array
(
       [0] => A:1
       [1] => B:a
       ...
)

down

-36

Anonymous ¶

8 years ago


As for the php 5.5.3 version, the example will turn out like:
Array
(
       [0]=>A:1
       [1]=>B:a
       ...
)

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