Suppose I have an arr开发者_运维百科ay of nodes (objects). I need to create a duplicate of this array that I can modify without affecting the source array. But changing the nodes will affect the source nodes. Basically maintaining pointers to the objects instead of duplicating their values.
// node(x, y)
$array[0] = new node(15, 10);
$array[1] = new node(30, -10);
$array[2] = new node(-2, 49);
// Some sort of copy system
$array2 = $array;
// Just to show modification to the array doesn't affect the source array
array_pop($array2);
if (count($array) == count($array2))
echo "Fail";
// Changing the node value should affect the source array
$array2[0]->x = 30;
if ($array2[0]->x == $array[0]->x)
echo "Goal";
What would be the best way to do this?
If you use PHP 5:
Have you run your code? It is already working, no need to change anything. I get:
Goal
when I run it.
Most likely this is because the values of $array
are already references.
Read also this question. Although he OP wanted to achieve the opposite, it could be helpful to understand how array copying works in PHP.
Update:
This behaviour, when copying arrays with objects, the reference to the object is copied instead the object itself, was reported as a bug. But no new information on this yet.
If you use PHP 4:
(Why do you still use it?)
You have to do something like:
$array2 = array();
for($i = 0; $i<count($array); $i++) {
$array2[$i] = &$array[$i];
}
it is some time that I don' write PHP code, but does the code
// Some sort of copy system
$array2 = $array;
actually work?
Don't you have to copy each element of the array in a new one?
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