Specifically, I would like to create an Array class and would like to overload the [] operator.
66
votes
6 Answers
54
votes
If you are using PHP5 (and you should be), take a look at the SPL ArrayObject classes. The documentation isn't too good, but I think if you extend ArrayObject, you'd have your "fake" array.
EDIT: Here's my quick example; I'm afraid I don't have a valuable use case though:
class a extends ArrayObject {
public function offsetSet($i, $v) {
echo 'appending ' . $v;
parent::offsetSet($i, $v);
}
}
$a = new a;
$a[] = 1;
27
votes
Actually, the optimal solution is to implement the four methods of the ArrayAccess interface: http://php.net/manual/en/class.arrayaccess.php
If you would also like to use your object in the context of 'foreach', you'd have to implement the 'Iterator' interface: http://www.php.net/manual/en/class.iterator.php
23
votes
PHP's concept of overloading and operators (see Overloading, and Array Operators) is not like C++'s concept. I don't believe it is possible to overload operators such as +, -, [], etc.
Possible Solutions
- Implement SPL ArrayObject (as mentioned by cbeer).
- Implement Iterator (if
ArrayObjectis too slow for you). - Use the PECL operator extension (as mentioned by Benson).
9
votes
For a simple and clean solution in PHP 5.0+, you need to implements the ArrayAccess interface and override functions offsetGet, offsetSet, offsetExists and offsetUnset. You can now use the object like an array.
Example:
<?php
class A implements ArrayAccess {
private $data = array();
public function offsetGet($offset) {
return isset($this->data[$offset]) ? $this->data[$offset] : null;
}
public function offsetSet($offset, $value) {
if ($offset === null) {
$this->data[] = $value;
} else {
$this->data[$offset] = $value;
}
}
public function offsetExists($offset) {
return isset($this->data[$offset]);
}
public function offsetUnset($offset) {
unset($this->data[$offset]);
}
}
$obj = new A;
$obj[] = 'a';
$obj['k'] = 'b';
echo $obj[0], $obj['k']; // print "ab"
1
votes
-1
votes
