PHP FILTER_CALLBACK filter

Definition and usage

The FILTER_CALLBACK filter calls user-defined functions to filter data.

This filter gives us full control over data filtering.

The specified function must be stored in an associative array named "options". See examples below.

Name: "callback"

ID-number: 1024

Tips and Notes

Tip: You can create your own function, or use an existing PHP function.

Example 1

Use user-defined functions:

 <?phpfunction convertSpace($string) { return str_replace(" ", "_", $string); }$string = "Peter is a great guy!";echo filter_var($string, FILTER_CALLBACK,array("options"= >"convertSpace"));?>

The output of the code looks like this:

 Peter_is_a_great_guy!

Example 2

Use existing PHP functions:

 <?php$string="Peter is a great guy!";echo filter_var($string, FILTER_CALLBACK,array("options"=>"strtoupper"));?>

The output of the code looks like this:

 PETER IS A GREAT GUY!