# mb_ereg_replace_callback

(PHP 5 >= 5.4.1, PHP 7)

mb_ereg_replace_callback — Perform a regular expression search and replace with multibyte support using a callback

### 说明

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

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`.

### 参数

`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`

  The search option. See mb_regex_set_options() for explanation.

### 返回值

The resultant string on success, or `FALSE` on error.

### 注释

> Note:

> mb_regex_encoding() 指定的内部编码或字符编码将会当作此函数用的字符编码。

### 范例

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);

    ?>

以上例程会输出：

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

Example #2 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);
    ?>

### 参见

- mb_regex_encoding() - Set/Get character encoding for multibyte regex
- mb_ereg_replace() - Replace regular expression with multibyte support
- Anonymous functions
- callback 类型的信息