(PHP 5 >= 5.1.0, PHP 7, PHP 8)
ArrayObject::exchangeArray — Exchange the array for another one
$array
) : arrayExchange the current array with another array or object.
arrayThe new array or object to exchange with the current array.
Returns the old array.
Example #1 ArrayObject::exchangeArray() example
<?php
// Array of available fruits
$fruits = array("lemons" => 1, "oranges" => 4, "bananas" => 5, "apples" => 10);
// Array of locations in Europe
$locations = array('Amsterdam', 'Paris', 'London');
$fruitsArrayObject = new ArrayObject($fruits);
// Now exchange fruits for locations
$old = $fruitsArrayObject->exchangeArray($locations);
print_r($old);
print_r($fruitsArrayObject);
?>
以上例程会输出：
Array
(
[lemons] => 1
[oranges] => 4
[bananas] => 5
[apples] => 10
)
ArrayObject Object
(
[0] => Amsterdam
[1] => Paris
[2] => London
)
Looks like PHP8 brings undocumented change to this method signature. Example:
<?php
interface intA {
public function exchangeArray($param);
}
class classB extends ArrayObject implements intA {}
?>
PHP 7.4.13: no errors
PHP 8.0.0: Fatal error: Declaration of ArrayObject::exchangeArray(object|array $array) must be compatible with intA::exchangeArray($param)
It's worth notting that ArrayObject::exchangeArray() doesn't call ArrayObject::offsetSet() internally for each offset/property of the array/object provided in argument.
It's also worth noting the let's say "unexpected" behavior of get/set:
<?php
class MyArrayObject extends ArrayObject
{
public function offsetSet($name, $value)
{
parent::offsetSet($name . '_control', $value);
parent::offsetSet($name, $value);
}
}
$test = new MyArrayObject();
$test->setFlags(\ArrayObject::ARRAY_AS_PROPS);
$test['my_value_1'] = 1;
$test['my_value_1'] = $test['my_value_1'] + 1;
$test['my_value_1'] += 1;
$test['my_value_1'] ++;
++ $test['my_value_1'];
$test->my_value_2 = 1;
$test->my_value_2 = $test->my_value_2 + 1;
$test->my_value_2 += 1;
$test->my_value_2 ++;
++ $test->my_value_2;
print_r($test);
// Prints out:
MyArrayObject Object
(
[storage:ArrayObject:private] => Array
(
[my_value_1_control] => 3
[my_value_1] => 5
[my_value_2_control] => 2
[my_value_2] => 5
)
)
?>
It seems that input array is always passed by reference.
For example if you have an existing array
$array with some values
then you have an arrayobject $o
and then you do this:
$o->exchangeArray($array);
$o->offsetSet('somekey', 'some value');
Now if you check your $array array, it will have
a key 'somekey' with value of 'some value'
I totally did not expect that, I am sure it was a mistake to pass array by reference by default.