php man page for filter_list

FILTER_LIST(3)								 1							    FILTER_LIST(3)

filter_list - Returns a list of all supported filters

SYNOPSIS
       array filter_list (void	)

DESCRIPTION
RETURN VALUES
	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(3) from a name instead.

EXAMPLES
       Example #1

	      A filter_list(3) 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
	      )

PHP Documentation Group 													    FILTER_LIST(3)