hi I working with Drupal and it uses arrays 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.