preg_filter

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

preg_filter — Perform a regular expression search and replace

Опис

preg_filter() is identical to preg_replace() except it only returns the (possibly transformed) subjects where there was a match. For details about how this function works, read the preg_replace() documentation.

Параметри

Parameters are described in the documentation for preg_replace().

Значення, що повертаються

Returns an array if the subject parameter is an array, or a string otherwise.

If no matches are found or an error occurred, an empty array is returned when subject is an array or null otherwise.

Помилки/виключення

Якщо задано хибний шаблон регулярного виразу, виведеться повідомлення рівня E_WARNING.

Приклади

Приклад #1 Example comparing preg_filter() with preg_replace()

<?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)); 
?>

Поданий вище приклад виведе:

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
)

Прогляньте також

PCRE Patterns
preg_quote() - Quote regular expression characters
preg_replace() - Perform a regular expression search and replace
preg_replace_callback() - Perform a regular expression search and replace using a callback
preg_grep() - Return array entries that match the pattern
preg_last_error() - Returns the error code of the last PCRE regex execution

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User Contributed Notes 3 notes

down

forsoap at gmail dot com ¶

8 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');
?>

down

bienvenunet at yahoo dot com ¶

7 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']
?>

down

sajina_99 at hotmail dot de ¶

13 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 ;
      
    }
    
  }
?>

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