PHP-数组对象去除重复的值

Question

Array
(
    [4968] => WP_Post Object
        (
            [ID] => 4968
            [post_author] => 1
            [post_date] => 2013-11-30 14:32:54
            [post_date_gmt] => 2013-11-30 06:32:54
            [post_content] => 
            [post_title] => taibei
            [post_excerpt] => 来到台北的日子
            [post_status] => inherit
            [comment_status] => open
            [ping_status] => open
            [post_password] => 
            [post_name] => taibei
            [to_ping] => 
            [pinged] => 
            [post_modified] => 2013-11-30 14:32:54
            [post_modified_gmt] => 2013-11-30 06:32:54
            [post_content_filtered] => 
            [post_parent] => 4058
            [guid] => http://tanteng-wordpress.stor.sinaapp.com/uploads/2013/01/taibei.jpg
            [menu_order] => 0
            [post_type] => attachment
            [post_mime_type] => image/jpeg
            [comment_count] => 0
            [filter] => raw
        )

    [4951] => WP_Post Object
        (
            [ID] => 4951
            [post_author] => 1
            [post_date] => 2013-11-29 14:38:33
            [post_date_gmt] => 2013-11-29 06:38:33
            [post_content] => 
            [post_title] => taipei
            [post_excerpt] => 台北路的生活
            [post_status] => inherit
            [comment_status] => open
            [ping_status] => open
            [post_password] => 
            [post_name] => taipei-3
            [to_ping] => 
            [pinged] => 
            [post_modified] => 2013-11-29 14:38:33
            [post_modified_gmt] => 2013-11-29 06:38:33
            [post_content_filtered] => 
            [post_parent] => 4058
            [guid] => http://tanteng-wordpress.stor.sinaapp.com/uploads/2013/01/taipei.jpgpsid1
            [menu_order] => 0
            [post_type] => attachment
            [post_mime_type] => image/jpeg
            [comment_count] => 0
            [filter] => raw
        )

    [4940] => WP_Post Object
        (
            [ID] => 4940
            [post_author] => 1
            [post_date] => 2013-11-28 12:53:08
            [post_date_gmt] => 2013-11-28 04:53:08
            [post_content] => 
            [post_title] => 201304181305293855
            [post_excerpt] => 
            [post_status] => inherit
            [comment_status] => open
            [ping_status] => open
            [post_password] => 
            [post_name] => 201304181305293855
            [to_ping] => 
            [pinged] => 
            [post_modified] => 2013-11-28 12:53:08
            [post_modified_gmt] => 2013-11-28 04:53:08
            [post_content_filtered] => 
            [post_parent] => 4509
            [guid] => http://tanteng-wordpress.stor.sinaapp.com/uploads/2013/09/201304181305293855.pngpsid1
            [menu_order] => 0
            [post_type] => attachment
            [post_mime_type] => image/png
            [comment_count] => 0
            [filter] => raw
        )

    [4937] => WP_Post Object
        (
            [ID] => 4937
            [post_author] => 1
            [post_date] => 2013-11-28 09:55:07
            [post_date_gmt] => 2013-11-28 01:55:07
            [post_content] => 
            [post_title] => wordpress-custom-query-string
            [post_excerpt] => 
            [post_status] => inherit
            [comment_status] => open
            [ping_status] => open
            [post_password] => 
            [post_name] => wordpress-custom-query-string
            [to_ping] => 
            [pinged] => 
            [post_modified] => 2013-11-28 09:55:07
            [post_modified_gmt] => 2013-11-28 01:55:07
            [post_content_filtered] => 
            [post_parent] => 4936
            [guid] => http://tanteng-wordpress.stor.sinaapp.com/uploads/2013/11/wordpress-custom-query-string.jpg
            [menu_order] => 0
            [post_type] => attachment
            [post_mime_type] => image/jpeg
            [comment_count] => 0
            [filter] => raw
        )

    [4931] => WP_Post Object
        (
            [ID] => 4931
            [post_author] => 1
            [post_date] => 2013-11-27 10:41:47
            [post_date_gmt] => 2013-11-27 02:41:47
            [post_content] => 
            [post_title] => yming
            [post_excerpt] => 
            [post_status] => inherit
            [comment_status] => open
            [ping_status] => open
            [post_password] => 
            [post_name] => psb-1
            [to_ping] => 
            [pinged] => 
            [post_modified] => 2013-11-27 10:41:47
            [post_modified_gmt] => 2013-11-27 02:41:47
            [post_content_filtered] => 
            [post_parent] => 0
            [guid] => http://tanteng-wordpress.stor.sinaapp.com/uploads/2013/11/psb-1.jpg
            [menu_order] => 0
            [post_type] => attachment
            [post_mime_type] => image/jpeg
            [comment_count] => 0
            [filter] => raw
        )

)