Php – ‘Cannot use object of type stdClass as array’ using WordPress

arraysPHPtagsWordpress

I am trying to retrieve the slug for a tag inside a wordpress post, now its possible to get all tag info using

$tag = wp_get_post_tags($post->ID);

More info on this on the WordPress Docs

By using this you should get data returned like this…

Array
(
   [0] => stdClass Object
       (
           [term_id] => 4
           [name] => tag2
           [slug] => tag2
           [term_group] => 0
           [term_taxonomy_id] => 4
           [taxonomy] => post_tag
           [description] => 
           [parent] => 0
           [count] => 7
       )

   [1] => stdClass Object
       (
           [term_id] => 7
           [name] => tag5
           [slug] => tag5
           [term_group] => 0
           [term_taxonomy_id] => 7
           [taxonomy] => post_tag
           [description] => 
           [parent] => 0
           [count] => 6
       )

)

Now what I want is the slug for the first item which should be as follows

$tag[0]['slug']

However by doing so I recieve this php error:

Cannot use object of type stdClass as
array

Can someone tell me what I'm doing wrong here? and whats the best way to get the slug data

Best Answer

Note that the array contains objects (instances of stdClass), not other arrays. So the syntax is:

$tag[0]->slug

Related Solutions

Javascript – Why is using “for…in” for array iteration a bad idea

The reason is that one construct:

var a = []; // Create a new empty array.
a[5] = 5;   // Perfectly legal JavaScript that resizes the array.

for (var i = 0; i < a.length; i++) {
    // Iterate over numeric indexes from 0 to 5, as everyone expects.
    console.log(a[i]);
}

/* Will display:
   undefined
   undefined
   undefined
   undefined
   undefined
   5
*/

can sometimes be totally different from the other:

var a = [];
a[5] = 5;
for (var x in a) {
    // Shows only the explicitly set index of "5", and ignores 0-4
    console.log(x);
}

/* Will display:
   5
*/

Also consider that JavaScript libraries might do things like this, which will affect any array you create:

// Somewhere deep in your JavaScript library...
Array.prototype.foo = 1;

// Now you have no idea what the below code will do.
var a = [1, 2, 3, 4, 5];
for (var x in a){
    // Now foo is a part of EVERY array and 
    // will show up here as a value of 'x'.
    console.log(x);
}

/* Will display:
   0
   1
   2
   3
   4
   foo
*/

Php – Convert a PHP object to an associative array

Just typecast it

$array = (array) $yourObject;

From Arrays:

If an object is converted to an array, the result is an array whose elements are the object's properties. The keys are the member variable names, with a few notable exceptions: integer properties are unaccessible; private variables have the class name prepended to the variable name; protected variables have a '*' prepended to the variable name. These prepended values have null bytes on either side.

Example: Simple Object

$object = new StdClass;
$object->foo = 1;
$object->bar = 2;

var_dump( (array) $object );

Output:

array(2) {
  'foo' => int(1)
  'bar' => int(2)
}

Example: Complex Object

class Foo
{
    private $foo;
    protected $bar;
    public $baz;

    public function __construct()
    {
        $this->foo = 1;
        $this->bar = 2;
        $this->baz = new StdClass;
    }
}

var_dump( (array) new Foo );

Output (with \0s edited in for clarity):

array(3) {
  '\0Foo\0foo' => int(1)
  '\0*\0bar' => int(2)
  'baz' => class stdClass#2 (0) {}
}

Output with var_export instead of var_dump:

array (
  '' . "\0" . 'Foo' . "\0" . 'foo' => 1,
  '' . "\0" . '*' . "\0" . 'bar' => 2,
  'baz' =>
  stdClass::__set_state(array(
  )),
)

Typecasting this way will not do deep casting of the object graph and you need to apply the null bytes (as explained in the manual quote) to access any non-public attributes. So this works best when casting StdClass objects or objects with only public properties. For quick and dirty (what you asked for) it's fine.

Also see this in-depth blog post:

Fast PHP Object to Array conversion

Best Answer

Related Solutions

Javascript – Why is using “for…in” for array iteration a bad idea

Php – Convert a PHP object to an associative array

Related Topic