Add properties to object using array keys

Question

Is it possible to have a construct like this. Say I have an array like this:

$names = array ('name1', 'name2', 'name3');
$values = array ('value1', 'value2', 'value3');

And then I want to do the following:

foreach ($names as $field) {
    $this->$field = $values[$counter];
    $counter ++;
}

So that later, I can access the said object like this:

$var1 = $object->name1;
$var2 = $object->name2;

// produces "value1"
echo $var1;

// produces "value2"
echo $var2;

What I want to do is to have an object, that has dynamically named fields. Is this possible with OO PHP?

Yes it is. Have you not tried it? Although the above code wont work, because you need to do `foreach ($names as $k => $name) $this->$name = $values[$k];` — DaveRandom, Sep 02 '11 at 15:53
@DaveRandom: code works with `$counter`. Not the way I'd go but the result is the same. — webbiedave, Sep 02 '11 at 15:56
I think this question was already answered here: http://stackoverflow.com/questions/829823/can-you-create-class-properties-dynamically-in-php — Sam, Sep 02 '11 at 16:00
@webbiedave surely that won't work unless you create the `$counter` variable with a value of zero first? I'm absolutely positive it wont work on the first iteration... — DaveRandom, Sep 02 '11 at 16:10
@DaveRandom: That's right. Since he's only showing code snippets I'm just assuming that it's initialized before the loop. — webbiedave, Sep 02 '11 at 16:47

score 4 · Answer 1 · answered Sep 02 '11 at 16:02

Yep, that'll work, but generally Variable Variables are discouraged.

Perhaps the more elegant solution would be to use the __get magic method on the class like so:

class Person
{
    public function __construct($vars)
    {
        $this->vars = $vars;
    }

    public function __get($var)
    {
        if (isset($this->vars[$var])) {
            return $this->vars[$var];
        }

        return null;
    }
}

The vars array would then work as so:

$vars = array(
    'name1' => 'value1', 
    'name2' => 'value2', 
    'name3' => 'value3',
);

$object = new Person($vars);

Or if you specifically want to build it from the two arrays:

$vars = array_combine($names, $values)

ajreal · Accepted Answer · 2011-09-02T16:06:49.193

3

Yes, you can

$object = (object)array_combine($names , $values);

As suggested by @Sam, the Magic __set method works better

edited Sep 02 '11 at 16:06

answered Sep 02 '11 at 15:52

ajreal

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score 1 · Answer 3 · answered Sep 02 '11 at 16:07

Using a specially-configured ArrayObject, you can access members using either syntax:

$object = new ArrayObject(array_combine($names, $values), ArrayObject::ARRAY_AS_PROPS);

echo $object->name1;   // value1
echo $object['name1']; // value1

Add properties to object using array keys

3 Answers3

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