mb_ereg_replace_callback

(PHP 5 >= 5.4.1, PHP 7)

Perform a regular expresssion seach and replace with multibyte support using a callback

string mb_ereg_replace_callback ( string $pattern, callable $callback, string $string [, string $option = "msr" ] )

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.

option

Matching condition can be set by option parameter. If i is specified for this parameter, the case will be ignored. If x is specified, white space will be ignored. If m is specified, match will be executed in multiline mode and line break will be included in '.'. If p is specified, match will be executed in POSIX mode, line break will be considered as normal character. Note that e cannot be used for mb_ereg_replace_callback().

Returns:

The resultant string on success, or FALSE on error.

Notes:

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

Examples:

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

mb_ereg_replace_callback() using anonymous function supported in PHP 5.3.0 or later

<?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);
?>