我可以通过使一个数组等于另一个数组来分配它吗?

让我们试一下:

$a = array(0,1,2);
$b = $a;
$b[0] = 5;

print_r($a);
print_r($b);

给予

Array
(
    [0] => 0
    [1] => 1
    [2] => 2
)
Array
(
    [0] => 5
    [1] => 1
    [2] => 2
)

以及 documentation

数组分配总是涉及 . 使用引用运算符按引用复制数组。

不,复印件不能改变原件。

$a = array(1,2,3,4,5);
$b = &$a;
$b[2] = 'AAA';
print_r($a);

数组按值复制。这里有一个gotcha tho。如果某个元素是引用,则该引用将被复制,但引用的对象相同。

<?php
class testClass {
    public $p;
    public function __construct( $p ) {
        $this->p = $p;
    }
}

// create an array of references
$x = array(
    new testClass( 1 ),
    new testClass( 2 )
);
//make a copy
$y = $x;

print_r( array( $x, $y ) );
/*
both arrays are the same as expected
Array
(
    [0] => Array
        (
            [0] => testClass Object
                (
                    [p] => 1
                )

            [1] => testClass Object
                (
                    [p] => 2
                )

        )

    [1] => Array
        (
            [0] => testClass Object
                (
                    [p] => 1
                )

            [1] => testClass Object
                (
                    [p] => 2
                )

        )

)
*/

// change one array
$x[0]->p = 3;

print_r( array( $x, $y ) );
/*
the arrays are still the same! Gotcha
Array
(
    [0] => Array
        (
            [0] => testClass Object
                (
                    [p] => 3
                )

            [1] => testClass Object
                (
                    [p] => 2
                )

        )

    [1] => Array
        (
            [0] => testClass Object
                (
                    [p] => 3
                )

            [1] => testClass Object
                (
                    [p] => 2
                )

        )

)
*/