how to refrence a nested class value by array value

Question

I think the best way to explain my question is to give an example. Say I have the following object.

$data=new stdClass;
$data->test=new stdClass;
$data->test->test2=6;
$data->s=array('b',6,7);

I want to know how I can read or change any value in the object given the key value as an array.

I know the below won't work:

function doSomething($inputArray1,$inputArray2) {
    $data[  $inputArray1   ]; //6
    $data[  $inputArray2   ]=4; //was array('b',6,7);
}

//someone else provided
doSomething( array('test','test2')  , array('s')  );

Changed to make clear that I do not know the values of the array personally so using $data->test->test2; to get the 6 like I normally would won't work. Also do not know the array length.

You want to change the objects array value? $data->s[2]?

Darren
– Darren

2016-11-02 04:52:46 +00:00
Commented Nov 2, 2016 at 4:52 — Darren
– Darren, Commented Nov 2, 2016 at 4:52

Matthew Cornelisse · Accepted Answer · 2016-11-02 12:37:27Z

1

Figured it out:

$parts=array('test','test2');


$ref=&$data;
foreach($parts as $part) {
    if (is_array($ref)) {
        $ref=&$ref[$part]; //refrence next level if array
    } else {
        $ref=&$ref->$part; //refrence next level if object
    }
}
echo $ref; //show value refrenced by array
$ref=4; //change value refrenced by array(surprised this works instead of making $ref=4 and breaking the refrence)
unset($ref); //get rid of refrence to prevent accidental setting.  Thanks @mpyw

edited Nov 2, 2016 at 12:37

answered Nov 2, 2016 at 11:44

Matthew Cornelisse

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2 Comments

mpyw Over a year ago

Execution unset($ref); is strongly recommended after your task is finished.

Matthew Cornelisse Over a year ago

thanks @mpyw I am sure that would have caused me all kinds of headaches.

Darren · Accepted Answer · 2016-11-02 05:16:36Z

0

As I noted in the comments, you need to access the object/arrays as intended. Their notations are as follows;

Object: ->
Array: []

So, taking your $data array you've generated, you'd have to access the object/array combination as such:

echo $data->s[2];

^Example/Demo

And if you were to access the initial test/test2 itteration (which is set as an object (->)), then you need to access it as an object:

echo $data->test->test2;

answered Nov 2, 2016 at 5:16

Darren

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1 Comment

Matthew Cornelisse Over a year ago

that is how I would normally do it if I knew the values in the array. I do not.

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