php array selector unsure of differnce

hi I working with Drupal and it uses arra开发者_StackOverflow中文版ys to a level I'm not very familier with, I've a quick question which is what is the difference between these 'selectors'(is that the right term)?

This causes an error "Fatal error: Cannot use object of type stdClass as array in..."

$node['field_geoloc'] 

this works (im using it in an if != null statement)

$node->field_geoloc

hopefully an easy question... thanks.

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Pretty easy.. the error says it all:

"Fatal error: Cannot use object of type stdClass as array in..."

You are attempting to use an object as an array.

Object properties aren't accessibly using the $array['key'] method that you are used to. You need to access properties like:

`$object->property`

If you have an object, you can get the properties from that array by using the get_object_vars method. But I know from experience that you should not use that method with a $node in Drupal.

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-> is operator for accessing public object properties (and call public methods). In order for an object properties to be accessed with $object['key'] syntax, it have to implement ArrayAccess. Other option is to cast the object to array ( $node = (array) $node (but this will work only for first-level keys, e.g. it will turn $node->page to $node['page'], but not $node->page->title to $node['page']['title'] - the later will be accessible via $node['page']->title

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Because you can't use object as an array.

That first is an array and that second is an object.

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The first one is an array, the second one is an object (of class StdClass). But you may be interested in this interface: http://php.net/manual/en/class.arrayaccess.php which allows accessing an object as an array (so you do $obj['key'] instead of $obj->key)