how to change a class variable array from outside the class?

Question

I need to change an array from outside the class, which is a class variable. For example see my code below:

<?php
class ArrayRet
{
    private $_ar = array();

    public function __construct()
    {
        $this->_ar['test1'] = 'hello1';
        $this->_ar['test2'] = 'hello2';
    }

    public function getAr()
    {
        return $this->_ar;
    }

    public function dump()
    {
        var_dump($this->_ar);
    }
}

$arRet = new ArrayRet();
$arRet->dump();
$ar = $arRet->getAr();
$ar['test2'] = 'works!!!';
$arRet->dump();
?>

$this->_ar['test2'] should be works!!! but it´s still hello2

How can I get this working?

Edit: With changing the syntax a bit as found here, it works. So, we need to change the method to this:

public function &getAr()
{
   return $this->_ar;
}

And also the call to this:

$ar = &$arRet->getAr();

Morteza Soltanabadiyan · Accepted Answer · 2014-08-16 20:43:18Z

2

you made 2 mistake : 1- you put your array in $ar and you changed it, so you changed $ar,Not $arRet, so your object Not changed. 2- you set _ar as private,so you can't change it directly, so you must make another function to change it. some thing like :

    <?php
    class ArrayRet
    {
        private $_ar = array();

        public function __construct()
        {
            $this->_ar['test1'] = 'hello1';
            $this->_ar['test2'] = 'hello2';
        }

        public function getAr()
        {
            return $this->_ar;
        }
        public function dump()
        {
            var_dump($this->_ar);
        }
        public function change_var($key,$val)
        {
           $this->_ar[$key] = $val;
        }
    }

    $arRet = new ArrayRet();
    $arRet->dump();
    $arRet->change_var('test1','works!!!');
    $ar = $arRet->getAr();

    $arRet->dump();
var_dump($ar);
    ?>

as you see $arRet changed and you put it into $ar.

edited Aug 16, 2014 at 20:43

answered Aug 16, 2014 at 20:35

Morteza Soltanabadiyan

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1 Comment

alpham8 Over a year ago

as far as I know, if I return a class variable, I give a reference back to the caller. But PHP copies it. And return &$this->_ar; gives me a syntax error.

Insyte · Accepted Answer · 2014-08-16 20:27:20Z

1

With your current code you can't as you have declared the visibility of ArrayRet::$_ar to be private meaning it cannot be accessed outside the scope of the class.

By declaring ArrayRet::$_ar as public you can do the following...

class ArrayRet
{
    public $_ar = array();
    // ...
}

$arRet = new ArrayRet();
$arRet->_ar['test2'] = 'works!!!';
$arRet->dump();

I don't recommend directly modifying object properties from outside of the class as this can cause headaches.

answered Aug 16, 2014 at 20:27

Insyte

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