1--TEST-- 2Test array_filter() function : usage variations - built-in functions as 'callback' argument 3--FILE-- 4<?php 5/* Prototype : array array_filter(array $input [, callback $callback]) 6 * Description: Filters elements from the array via the callback. 7 * Source code: ext/standard/array.c 8*/ 9 10/* 11* Passing built-in functions and different language constructs as 'callback' argument 12*/ 13 14echo "*** Testing array_filter() : usage variations - built-in functions as 'callback' argument ***\n"; 15 16$input = array(0, 1, -1, 10, 100, 1000, 'Hello', null); 17 18// using built-in function 'is_int' as 'callback' 19var_dump( array_filter($input, 'is_int') ); 20 21// using built-in function 'chr' as 'callback' 22var_dump( array_filter($input, 'chr') ); 23 24// using language construct 'echo' as 'callback' 25var_dump( array_filter($input, 'echo') ); 26 27// using language construct 'exit' as 'callback' 28var_dump( array_filter($input, 'exit') ); 29 30echo "Done" 31?> 32--EXPECTF-- 33*** Testing array_filter() : usage variations - built-in functions as 'callback' argument *** 34array(6) { 35 [0]=> 36 int(0) 37 [1]=> 38 int(1) 39 [2]=> 40 int(-1) 41 [3]=> 42 int(10) 43 [4]=> 44 int(100) 45 [5]=> 46 int(1000) 47} 48array(8) { 49 [0]=> 50 int(0) 51 [1]=> 52 int(1) 53 [2]=> 54 int(-1) 55 [3]=> 56 int(10) 57 [4]=> 58 int(100) 59 [5]=> 60 int(1000) 61 [6]=> 62 string(5) "Hello" 63 [7]=> 64 NULL 65} 66 67Warning: array_filter() expects parameter 2 to be a valid callback, function 'echo' not found or invalid function name in %s on line %d 68NULL 69 70Warning: array_filter() expects parameter 2 to be a valid callback, function 'exit' not found or invalid function name in %s on line %d 71NULL 72Done 73