PHP 7.4.22 Released!

mb_ereg_replace_callback

(PHP 5 >= 5.4.1, PHP 7, PHP 8)

mb_ereg_replace_callbackPerform a regular expression search and replace with multibyte support using a callback

Description

mb_ereg_replace_callback(
    string $pattern,
    callable $callback,
    string $string,
    ?string $options = null
): string|false|null

Scans string for matches to pattern, then replaces the matched text with the output of callback function.

The behavior of this function is almost identical to mb_ereg_replace(), except for the fact that instead of replacement parameter, one should specify a callback.

Parameters

pattern

The regular expression pattern.

Multibyte characters may be used in pattern.

callback

A callback that will be called and passed an array of matched elements in the subject string. The callback should return the replacement string.

You'll often need the callback function for a mb_ereg_replace_callback() in just one place. In this case you can use an anonymous function to declare the callback within the call to mb_ereg_replace_callback(). By doing it this way you have all information for the call in one place and do not clutter the function namespace with a callback function's name not used anywhere else.

string

The string being checked.

options

The search option. See mb_regex_set_options() for explanation.

Return Values

The resultant string on success, or false on error. If string is not valid for the current encoding, null is returned.

Changelog

Version Description
8.0.0 options is nullable now.
7.1.0 The function checks whether string is valid for the current encoding.

Examples

Example #1 mb_ereg_replace_callback() example

<?php
// this text was used in 2002
// we want to get this up to date for 2003
$text "April fools day is 04/01/2002\n";
$text.= "Last christmas was 12/24/2001\n";
// the callback function
function next_year($matches)
{
  
// as usual: $matches[0] is the complete match
  // $matches[1] the match for the first subpattern
  // enclosed in '(...)' and so on
  
return $matches[1].($matches[2]+1);
}
echo 
mb_ereg_replace_callback(
            
"(\d{2}/\d{2}/)(\d{4})",
            
"next_year",
            
$text);

?>

The above example will output:

April fools day is 04/01/2003
Last christmas was 12/24/2002

Example #2 mb_ereg_replace_callback() using anonymous function

<?php
// this text was used in 2002
// we want to get this up to date for 2003
$text "April fools day is 04/01/2002\n";
$text.= "Last christmas was 12/24/2001\n";

echo 
mb_ereg_replace_callback(
            
"(\d{2}/\d{2}/)(\d{4})",
            function (
$matches) {
               return 
$matches[1].($matches[2]+1);
            },
            
$text);
?>

Notes

Note:

The internal encoding or the character encoding specified by mb_regex_encoding() will be used as the character encoding for this function.

See Also

add a note add a note

User Contributed Notes

There are no user contributed notes for this page.
To Top