How to call a callback function in a PHP class - php

Question

I want to use array_filter to remove those items in an array whose value is equal to a specific character like '.' . To do, so I used the following code but I don't know how to pass the callback function to array_filter:
class Myclass(){
private function isPunc($var){
if($var=='.'){
return TRUE;
}else{
return FALSE;
}
public function myfunction($arr){
$arr = array_filter($arr,"isPunc");
}
}
Any idea how to solve this problem?

Answer 1

class Myclass(){
private function isPunc($var) {
if ($var=='.') {
return TRUE;
} else {
return FALSE;
}
}
public function myfunction($arr) {
$arr = array_filter($arr, array($this,'isPunc'));
}
}

Answer 2

use $arr = array_filter($arr, array($this, 'isPunc'));

Answer 3

array_filter() expects a Callable. This is an special internal type in PHP that can be on of four things:
a string with function name
an array with an object and method name as elements
an anonymous function
a functor (an object that implements __invoke)
In your case the second variant should work:
class FilterIsDot {
private function accept($element) {
if($element == '.'){
return TRUE;
}else{
return FALSE;
}
}
public function filter($array) {
return array_filter(
$array, array($this, 'accept')
);
}
}
$in = array('.', 'foo');
$filter = new FilterIsDot();
var_dump($filter->filter($in));
I would suggest a different approach avoiding array_filter(). SPL contains a FilterIterator class. You can extends this class:
class FilterIsDot extends FilterIterator {
public function __construct($arrayOrIterator) {
parent::__construct(
is_array($arrayOrIterator)
? new ArrayIterator($arrayOrIterator)
: $arrayOrIterator
);
}
public function accept() {
if($this->current() == '.') {
return TRUE;
}else{
return FALSE;
}
}
}
$in = array('.', 'foo');
$filter = new FilterIsDot($in);
var_dump(iterator_to_array($filter));
In this case the filter works on the fly. It is only used if the elements are actually accessed.