(PHP 5, PHP 7, PHP 8)
ArrayObject::__construct — Construct a new array object
$input = array()
, int $flags = 0
, string $iterator_class = "ArrayIterator"
)This constructs a new array object.
input
The input parameter accepts an
array or an Object.
flagsFlags to control the behaviour of the ArrayObject object. See ArrayObject::setFlags().
iterator_classSpecify the class that will be used for iteration of the ArrayObject object.
Returns an ArrayObject object on success.
Throws InvalidArgumentException when:
input is not an array or object
flags is not an integer
iterator_class is not an object that implements
Iterator
Example #1 ArrayObject::__construct() example
<?php
$array = array('1' => 'one',
'2' => 'two',
'3' => 'three');
$arrayobject = new ArrayObject($array);
var_dump($arrayobject);
?>
以上例程会输出：
object(ArrayObject)#1 (3) {
[1]=>
string(3) "one"
[2]=>
string(3) "two"
[3]=>
string(5) "three"
}
The great confusion with this class is in its naming. ArrayObject infers it will behave as an Array and as an Object. It won't. It behaves as an array. It would better be called ArrayType. You can, with some work, get it to work both as an object and as an array, but that is up to you.
BTW, if you need to change array later, use exchangeArray() method. Good to know when you are writing a class that extends ArrayObject()
AFAIK, exchangeArray() doesn't return anything.
<?php
$a = array('one', 'two', 'three');
$ao = new ArrayObject($a);
foreach ($ao as $element) {
echo $element . ' '; // one two three
}
$b = array('four', 'five', 'six');
$ao->exchangeArray($b); // returns null
foreach ($ao as $element) {
echo $element . ' '; // four five six
}
?>
Note that the first argument to ArrayObject::__construct, the initial array, is passed by reference. Nevertheless, modification of the array doesn't modify the object, so it may cause unexpected behaviour.
<?php
$array = array('foo' => 'initial');
$obj = new ArrayObject($array);
// array was passed by reference:
$obj['foo'] = 'modified';
var_dump($array); // foo => modified
// but it doesn't work backwards:
$array['foo'] = 'modified_again';
var_dump($obj); // foo => modified
var_dump($array); // foo => modified_again
?>
As Marcus explained, the flag ArrayObject::SPL_ARRAY_AS_PROPS means the array element may be used as a property if there is no conflict with visible properties.
If there are visible properties in the class, the array element will not overwrite it's value.
<?php
class Rules extends ArrayObject {
public $len = 1;
function __construct($array){
parent::__construct($array,ArrayObject::ARRAY_AS_PROPS);
$this['len'] = 2;
}
}
$x = new Rules(array(1,2));
echo $x->len;
?>
Result: 1
<?php
class Rules extends ArrayObject {
private $len = 1;
function __construct($array){
parent::__construct($array,ArrayObject::ARRAY_AS_PROPS);
$this['len'] = 2;
}
}
$x = new Rules(array(1,2));
echo $x->len;
?>
Result: 2