mb_ereg_replace_callback
(PHP 5 >= 5.4.1, PHP 7, PHP 8)
mb_ereg_replace_callback — Perform a regular expression search and replace with multibyte support using a callback
Description
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
subjectstring. The callback should return the replacement string.You'll often need the
callbackfunction 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/\d/)(\d)",
"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";
$text.= "Last christmas was 12/24/2001\n";
echo mb_ereg_replace_callback(
"(\d/\d/)(\d)",
function ($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
- mb_regex_encoding() - Set/Get character encoding for multibyte regex
- mb_ereg_replace() - Replace regular expression with multibyte support
- Anonymous functions
