simplexml_load_file处理xml后，如何取出其中的某个特定的值？

SimpleXMLElement Object
(
    [defaultSort] => SimpleXMLElement Object
        (
        )    [pagesize] => 10
    [total] => 164
    [elapsed] => 1
    [result] => SimpleXMLElement Object
        (
            [record] => Array
                (
                    [0] => SimpleXMLElement Object
                        (
                            [pid] => 2085339416
                            [num] => 1
                            [img] => http://img.yeedou.com/images/01/150/3984150/4678266_200_200.jpg
                            [dbtitle] => 娆ц开鍔炲叕鍟嗗煄銆愯鍩轰簹锛圢OKIA锛塀H-304銆?
                            [dbdesc] => null
                            [lowprice] => 480.00
                            [highprice] => 480.00
                            [onecls] => 1
                            [twocls] => 1
                            [threecls] => 1
                            [shopid] => 1
                            [brandid] => 1
                        )                    [1] => SimpleXMLElement Object
                        (
                            [pid] => 2085360341
                            [num] => 1
                            [img] => http://img.yeedou.com/images/01/150/3984150/4678266_200_200.jpg
                            [dbtitle] => 娆ц开鍔炲叕鍟嗗煄銆愯鍩轰簹锛圢OKIA锛塀H-209銆?
                            [dbdesc] => null
                            [lowprice] => 220.00
                            [highprice] => 220.00
                            [onecls] => 1
                            [twocls] => 1
                            [threecls] => 1
                            [shopid] => 1
                            [brandid] => 1
                        )                    [2] => SimpleXMLElement Object
                        (
                            [pid] => 2085360465
                            [num] => 1
                            [img] => http://img.yeedou.com/images/01/150/3984150/4678266_200_200.jpg
                            [dbtitle] => 娆ц开鍔炲叕鍟嗗煄銆愯鍩轰簹锛圢OKIA锛塀H-208銆?
                            [dbdesc] => null
                            [lowprice] => 380.00
                            [highprice] => 380.00
                            [onecls] => 1
                            [twocls] => 1
                            [threecls] => 1
                            [shopid] => 1
                            [brandid] => 1
                        )                    [3] => SimpleXMLElement Object
                        (
                            [pid] => 344210203
                            [num] => 1
                            [img] => http://img.yeedou.com/images/01/150/3984150/4678266_200_200.jpg
                            [dbtitle] => 銆愮帺璐綉銆戣鍩轰簹(NOKIA)鍘熷巶鐢垫睜BL-6C鎶ヤ环
                            [dbdesc] => 浜у搧绫诲瀷:閿傜瀛愮數姹犻€傜敤鏈哄瀷:7700N-GAGEQD286560126015615261556165623562556265626821162125285531523155E70鎬ц兘姒傝堪:鍟嗗搧璇存槑
                            [lowprice] => 132.00
                            [highprice] => 132.00
                            [onecls] => 1
                            [twocls] => 1
                            [threecls] => 1
                            [shopid] => 1
                            [brandid] => 1
                        )                    [4] => SimpleXMLElement Object
                        (
                            [pid] => 344210234
                            [num] => 1
                            [img] => http://img.yeedou.com/images/01/150/3984150/4678266_200_200.jpg
                            [dbtitle] => 銆愮帺璐綉銆戣鍩轰簹(NOKIA)鍘熷巶鐢垫睜BL-5X鎶ヤ环
                            [dbdesc] => 浜у搧绫诲瀷:閿傜瀛愮數姹犻€傜敤鏈哄瀷:8800鎬ц兘姒傝堪:鍟嗗搧璇存槑
                            [lowprice] => 310.00
                            [highprice] => 310.00
                            [onecls] => 1
                            [twocls] => 1
                            [threecls] => 1
                            [shopid] => 1
                            [brandid] => 1
                        )                    [5] => SimpleXMLElement Object
                        (
                            [pid] => 361535376
                            [num] => 1
                            [img] => http://img.yeedou.com/images/01/150/3984150/4678266_200_200.jpg
                            [dbtitle] => 銆愮帺璐綉銆戣鍩轰簹(NOKIA)鍘熷巶鐢垫睜BL-4C鎶ヤ环
                            [dbdesc] => null
                            [lowprice] => 122.00
                            [highprice] => 122.00
                            [onecls] => 1
                            [twocls] => 1
                            [threecls] => 1
                            [shopid] => 1
                            [brandid] => 1
                        )                    [6] => SimpleXMLElement Object
                        (
                            [pid] => 361536058
                            [num] => 1
                            [img] => http://img.yeedou.com/images/01/150/3984150/4678266_200_200.jpg
                            [dbtitle] => 銆愮帺璐綉銆戣鍩轰簹(NOKIA)鍘熷巶鐢垫睜BP-5L鎶ヤ环
                            [dbdesc] => null
                            [lowprice] => 468.00
                            [highprice] => 468.00
                            [onecls] => 1
                            [twocls] => 1
                            [threecls] => 1
                            [shopid] => 1
                            [brandid] => 1
                        )                    [7] => SimpleXMLElement Object
                        (
                            [pid] => 361536151
                            [num] => 1
                            [img] => http://img.yeedou.com/images/01/150/3984150/4678266_200_200.jpg
                            [dbtitle] => 銆愮帺璐綉銆戣鍩轰簹(NOKIA)鍘熷巶鐢垫睜BP-6M鎶ヤ环
                            [dbdesc] => null
                            [lowprice] => 444.00
                            [highprice] => 444.00
                            [onecls] => 1
                            [twocls] => 1
                            [threecls] => 1
                            [shopid] => 1
                            [brandid] => 1
                        )                    [8] => SimpleXMLElement Object
                        (
                            [pid] => 361564144
                            [num] => 1
                            [img] => http://img.yeedou.com/images/01/150/3984150/4678266_200_200.jpg
                            [dbtitle] => 銆愮帺璐綉銆戣鍩轰簹(NOKIA)鍘熷巶鐢垫睜BL-5B鎶ヤ环
                            [dbdesc] => null
                            [lowprice] => 122.00
                            [highprice] => 122.00
                            [onecls] => 1
                            [twocls] => 1
                            [threecls] => 1
                            [shopid] => 1
                            [brandid] => 1
                        )                    [9] => SimpleXMLElement Object
                        (
                            [pid] => 361564175
                            [num] => 1
                            [img] => http://img.yeedou.com/images/01/150/3984150/4678266_200_200.jpg
                            [dbtitle] => 銆愮帺璐綉銆戣鍩轰簹(NOKIA)鍘熷巶鐢垫睜BL-4B鎶ヤ环
                            [dbdesc] => null
                            [lowprice] => 312.00
                            [highprice] => 312.00
                            [onecls] => 1
                            [twocls] => 1
                            [threecls] => 1
                            [shopid] => 1
                            [brandid] => 1
                        )                )        ))我想取出其中的pid和img值，怎么弄？谢谢！