PHP 7.0.6 Released

    ArrayObject::exchangeArray

    (PHP 5 >= 5.1.0, PHP 7)

    ArrayObject::exchangeArray — Exchange the array for another one.

    Description

    public array ArrayObject::exchangeArray ( mixed $input )

    Exchange the current array with another array or object.

    Parameters

    input

    The new array or object to exchange with the current array.

    Return Values

    Returns the old array.

    Examples

    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);

    ?>

    The above example will output:

    Array
(
    [lemons] => 1
    [oranges] => 4
    [bananas] => 5
    [apples] => 10
)
ArrayObject Object
(
    [0] => Amsterdam
    [1] => Paris
    [2] => London
)

    User Contributed Notes

    Dmitri Snytkine
    6 years ago
    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.
    Corentin Larose
    1 year ago
    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
                )
    )
    ?>
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