PHP preg_replace_callback() Function
Example
Count letters in all of the words in a sentence:
<?php
function countLetters($matches) {
return $matches[0] . '(' .
strlen($matches[0]) . ')';
}
$input = "Welcome to W3Schools.com!";
$pattern = '/[a-z0-9\.]+/i';
$result = preg_replace_callback($pattern,
'countLetters', $input);
echo $result;
?>
Try it Yourself »
Definition and Usage
The preg_replace_callback() function, given an expression and a callback, returns a string where all matches of the expression
are replaced with the substring returned by the callback function.
Syntax
preg_replace_callback(pattern, callback, input, limit, count)
Parameter Values
| Parameter | Description |
|---|---|
| pattern | Required. A regular expression or array of regular expressions indicating what to search for |
| replacements | Required. A callback function which returns the replacement. The callback function has one parameter containing an array of matches. The first element in the array contains the match for the whole expression while the remaining elements have matches for each of the groups in the expression. |
| input | Required. The string or array of strings in which replacements are being performed |
| limit | Optional. Defaults to -1, meaning unlimited. Sets a limit to how many replacements can be done in each string |
| count | Optional. After the function has executed, this variable will contain a number indicating how many replacements were performed |
Technical Details
| Return Value: | Returns a string or an array of strings resulting from applying the replacements to the input string or strings. |
|---|---|
| PHP Version: | 4.0.5+ |
| Changelog: | PHP 5.1.0 - The count parameter was added |
❮ PHP RegExp Reference
