How to Access an Object Property Named as a Variable in PHP

How can I access an object property named as a variable in php?

Since the name of your property is the string '$t', you can access it like this:

echo $object->{'$t'};

Alternatively, you can put the name of the property in a variable and use it like this:

$property_name = '$t';
echo $object->$property_name;

You can see both of these in action on repl.it: https://repl.it/@jrunning/SpiritedTroubledWorkspace

PHP - Accessing a object property from dynamic variable

I don't think you can make multiple dereferences this way. You'll be looking for a variable in $object called user->name. Instead, you can split by -> and then make multiple calls, something like:

$test = 'user->name';
$val = $object;
foreach(explode('->', $test) as $item) {
  $val = $val->$item;
}
echo $val;   # This is the result of $object->user->name

Sample Code

PHP - Get object properties by variable

This is how you can do it:

for ($i = 1; $i <= 20; $i++){
    $propertyName = "bullet$i";
    if ($objectName->$propertyName){
        echo $info->$propertyName;
    }
}

Though I think using an array instead of the object would be a better solution.

How can I access a deep object property named as a variable (dot notation) in php?

It is very easy to reduce the object path using variable property notation ($o->$p):

$path = 'foo.bar';
echo array_reduce(explode('.', $path), function ($o, $p) { return $o->$p; }, $user);

This could easily be turned into a small helper function.

PHP: Access Object Properties by String

Finally I have working code.

With mental support from @NigelRen

Emotional support from @FunkFortyNiner

And most of the code from this question about arrays

Test Object:

$obj = json_decode('{"snow":{"elevation":"365.4","results":"6","status":1},"wind":{"elevation":"365.4","windi":"100 mph","windii":"110 mph","windiii":"115 mph","status":1}}');

Test Directory:

$path = 'wind:windii';

Getter:

  function get($path, $obj) {
    $path = explode(':', $path);
    $temp =& $obj;

    foreach($path as $key) {
      $temp =& $temp->{$key};
    }
    return $temp;
  }
  var_dump(get($path, $obj)); //dump to see the result

Setter:

  function set($path, &$obj, $value=null) {
    $path = explode(':', $path);
    $temp =& $obj;

    foreach($path as $key) {
      $temp =& $temp->{$key};
    }

    $temp = $value;
  }
  //Tested with:
  set($path, $obj, '111');

How to access object properties with names like integers or invalid property names?

Updated for PHP 7.2

PHP 7.2 introduced a behavioral change to converting numeric keys in object and array casts, which fixes this particular inconsistency and makes all the following examples behave as expected.

One less thing to be confused about!

Original answer (applies to versions earlier than 7.2.0)

PHP has its share of dark alleys that you really don't want to find yourself inside. Object properties with names that are numbers is one of them...

What they never told you

Fact #1: You cannot access properties with names that are not legal variable names easily

$a = array('123' => '123', '123foo' => '123foo');
$o = (object)$a;
echo $o->123foo; // error

Fact #2: You can access such properties with curly brace syntax

$a = array('123' => '123', '123foo' => '123foo');
$o = (object)$a;
echo $o->{'123foo'}; // OK!

Fact #3: But not if the property name is all digits!

$a = array('123' => '123', '123foo' => '123foo');
$o = (object)$a;
echo $o->{'123foo'}; // OK!
echo $o->{'123'}; // error!

Live example.

Fact #4: Well, unless the object didn't come from an array in the first place.

$a = array('123' => '123');
$o1 = (object)$a;
$o2 = new stdClass;
$o2->{'123'} = '123'; // setting property is OK

echo $o1->{'123'}; // error!
echo $o2->{'123'}; // works... WTF?

Live example.

Pretty intuitive, don't you agree?

What you can do

Option #1: do it manually

The most practical approach is simply to cast the object you are interested in back into an array, which will allow you to access the properties:

$a = array('123' => '123', '123foo' => '123foo');
$o = (object)$a;
$a = (array)$o;
echo $o->{'123'}; // error!
echo $a['123']; // OK!

Unfortunately, this does not work recursively. So in your case you 'd need to do something like:

$highlighting = (array)$myVar->highlighting;
$data = (array)$highlighting['448364']->Data;
$value = $data['0']; // at last!

Option #2: the nuclear option

An alternative approach would be to write a function that converts objects to arrays recursively:

function recursive_cast_to_array($o) {
    $a = (array)$o;
    foreach ($a as &$value) {
        if (is_object($value)) {
            $value = recursive_cast_to_array($value);
        }
    }

    return $a;
}

$arr = recursive_cast_to_array($myVar);
$value = $arr['highlighting']['448364']['Data']['0'];

However, I 'm not convinced that this is a better option across the board because it will needlessly cast to arrays all of the properties that you are not interested in as well as those you are.

Option #3: playing it clever

An alternative of the previous option is to use the built-in JSON functions:

$arr = json_decode(json_encode($myVar), true);
$value = $arr['highlighting']['448364']['Data']['0'];

The JSON functions helpfully perform a recursive conversion to array without the need to define any external functions. However desirable this looks, it has the "nuke" disadvantage of option #2 and additionally the disadvantage that if there is any strings inside your object, those strings must be encoded in UTF-8 (this is a requirement of json_encode).

Access static object property through variable name

Use: Class::$$constName, this is similar to normal variable variables.

Demo:

<?php    
class MyClass {
    public static $var = 'A';
}
$name = 'var';
echo MyClass::$$name; // echoes 'A'

Constants can be access with the constant function:

constant('MyClass::'.$constantName)

PHP access object values dynamically by variable name

The script and this line

$obj = $properties->$action->item;

Are absolutely OK. But, as you pointed out in the comments,

If action = GetPropertyGroups, Undefined property:
stdClass::$GetPropertyGroups

You have PropertyGroups property in $properties, not GetPropertyGroups.

You should check if the property you're looking for exists:

property_exists($properties, $action)

How can I access an object attribute that starts with a number?

What about this :

$Beeblebrox->{'2ndhead'}

Actually, you can do this for pretty much any kind of variable -- even for ones that are not class properties.

For example, you could think about a variable's name that contains spaces ; the following syntax will work :

${"My test var"} = 10;
echo ${"My test var"};

Even if, obviously, you would not be able to do anything like this :

$My test var = 10;
echo $My test var;

No idea how it's working internally, though... And after a bit of searching, I cannot find anything about this in the PHP manual.

Only thing I can find about {} and variables is in here : Variable parsing -- but not quite related to the current subject...

But here's an article that shows a couple of other possiblities, and goes farther than the examples I posted here : PHP Variable Names: Curly Brace Madness

And here's another one that gives some additionnal informations about the way those are parsed : PHP grammar notes

Using a variable variable in an object property in PHP

This would work, you had the double $$ which wasn't needed in this instance.

 $field = "XYZ";
 $block_hi = $field."_hi";
 $block_lo = $field."_lo";

 print($node->{$block_hi}['val']);
 print($node->{$block_lo}['val']);