(PHP 5 >= 5.2.0, PHP 7)
filter_list — Returns a list of all supported filters
Returns an array of names of all supported filters, empty array if there are no such filters. Indexes of this array are not filter IDs, they can be obtained with filter_id() from a name instead.
Example #1 A filter_list() example
<?php
print_r(filter_list());
?>
The above example will output something similar to:
Array
(
[0] => int
[1] => boolean
[2] => float
[3] => validate_regexp
[4] => validate_url
[5] => validate_email
[6] => validate_ip
[7] => string
[8] => stripped
[9] => encoded
[10] => special_chars
[11] => unsafe_raw
[12] => email
[13] => url
[14] => number_int
[15] => number_float
[16] => magic_quotes
[17] => callback
)