array_item[] = $file what does this do?

Question

I have been following a tutorial on readdir(), is_dir() etc involved in setting up a small image gallery based on folders and files on my FTP. I was wondering what the $directorys[] = $file; part does specifically?

while( $file= readdir( $dir_handle ) )      
{
        if( is_dir( $file ) ){              
            $directorys[] = $file;          
        }else{                              
            $files[] = $file;               
        }
}

Answer 1

It pushes an item to the array, instead of array_push, it would only push one item to the array.

Using array_push and $array[] = $item works the same, but it's not ideal to use array_push as it's suitable for pushing multiple items in the array.

Example:

Array (
)

After doing this $array[] = 'This works!'; or array_push($array, 'This works!') it will appear as this:

Array (
   [0] => This works!
)

Also you can push arrays into an array, like so:

$array[] = array('item', 'item2');

Array (
   [0] => Array (
             [0] => item
             [1] => item2
          )
)