PHP provides a range of built-in functions for filtering and validating user input data. One such function is filter_list(), which is used to return a list of all available filters. In this article, we will provide you with a detailed guide on how to use filter_list() in PHP, its syntax, and its benefits.


The syntax for filter_list() is as follows:

filter_list ( void ) : array

The function takes no parameters and returns an array of all available filters.


The filter_list() function is used to return a list of all available filters in PHP. For example, the following code uses filter_list() to obtain a list of all available filters and displays them in a table:


$filters = filter_list();
echo "<table>";
echo "<tr><th>Filter ID</th><th>Filter Name</th></tr>";
foreach ($filters as $id => $name) {
    echo "<tr><td>$id</td><td>$name</td></tr>";
echo "</table>";

In this example, the code uses filter_list() to obtain a list of all available filters and then loops through the array to display the filter ID and name in a table.


Using filter_list() can help improve the security and reliability of your PHP application by providing a comprehensive list of all available filters. By validating input data before processing it, you can ensure that your application only accepts valid data and avoid potential security breaches.

Additionally, using filter functions can help improve the overall quality of your code by making it more readable and maintainable. By separating validation logic from processing logic, you can make your code more modular and easier to debug.


In conclusion, the filter_list() function is a useful tool for obtaining a list of all available filters in PHP applications. By using it in conjunction with other filter functions, you can improve the security and quality of your code, while also making it easier to read and maintain.

Practice Your Knowledge

Which of the following are valid filter names in PHP according to the information on the provided URL?

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