mb_ereg_replace_callback
Perform a regular expression search and replace with multibyte support using a callback
Description
stringfalsenull mb_ereg_replace_callback(
string $pattern,
callable $callback,
string $string,
stringnull $options = null
)
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 string 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.
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.