CODEWITHSUNDEEP
phparraysclassloopsvariable-assignment
hashbrown
hashbrown

Reputation: 3516

Running a loop through object properties and assign value

I have this class,

class example {
    public $a;
    public $b;
    public $c;
    ....
}

I have an array containing equal number of public variables as present in the example class (in this case 3):

$arr[0] = 'Red';
$arr[1] = 'Green';
$arr[2] = 'Blue';

I want to assign each value of this array to the public properties of the class one by one (Like $a gets Red, $b gets Green and so on). How do I assign these values from the array to the public properties of the class using a loop?

I was writing something like below, but it didn't work:

$class = new example();
$i = 0;
foreach ($class as $key => $value) {
    $class->$$key = $arr[$i];
    $i++;
}

EDIT:

Just to explain why I couldn't use any setter/getter method in example class - actually example class is created by unserializing a database object. I do not have any control on this class. I am working on a controller class which receives this example class and an array. I need to figure out a way to assign the values from this array to the public properties of example class.

Upvotes: 2

Views: 2913

Answers (3)

N.B.
N.B.

Reputation: 14071

Well, as I mentioned before - the approach is wrong. There are two answers that tell you how to do it, but it's not the best way.

This is a slightly better way, and it's smarter - because you have less code, less work and you can add as many properties as you want without ever touching the class.

The code:

class MyClass {

    protected $_data = array();

    public function setData(array $data)
    {
        $this->_data = $data;
    }

    public function __set($key, $value)
    {
        $this->_data[$key] = $value;
    }

    public function __get($key)
    {
        return isset($this->_data[$key]) ? $this->data[$key] : null;
    }
}

Usage scenario #1:

$class = new MyClass;

$class->red = 'My red value';
$class->blue = 'My blue value';

Usage scenario #2:

$class = new MyClass;

$class->setData( array('red' => 'Red', 'blue' => 'Blue', 'green' => 'Green') );

The example serves to steer you towards magic functions __get() and __set() which you can use to your advantage and code the class (with proper data and value checking) in such a way that it's usable without having to declare its properties. This reduces complexity. Or you can use one of the given answers if they fit your scenario in a satisfactory way.

Upvotes: 2

raidenace
raidenace

Reputation: 12836

Here you go:

<?php
class example {
    public $a;
    public $b;
    public $c;
}
$arr[0] = 'Red';
$arr[1] = 'Green';
$arr[2] = 'Blue';
$class = new example();
$i = 0;
foreach ($class as $key => $value) {
    $class->{$key} = $arr[$i];
    $i++;
}
var_dump($class);

The basic idea is to use $class->{$key} instead of $class->$$key, because $$key is a variable variable.

Upvotes: 1

MrCode
MrCode

Reputation: 64526

It doesn't work because of the double $$ when you assign the key:

$class->$$key = $arr[$i];

Change to a single $

$class->$key = $arr[$i];

Codepad demo

When accessing object properties without a variable, no $ is needed, therefore if your key is stored in a variable, a single $ is needed.

That said, there is likely a better way to solve the problem than this. Seems like the X Y Problem.

Upvotes: 2

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