php怎么从xml内容变量中获取节点值？高分奉上

Question

<?xml version="1.0" encoding="GBK"?><AIPG>
  <INFO>
    <TRX_CODE>100014</TRX_CODE>
    <VERSION>03</VERSION>
    <DATA_TYPE>2</DATA_TYPE>
    <REQ_SN>1377051780610</REQ_SN>
    <RET_CODE>0000</RET_CODE>
    <SIGNED_MSG>1db0a12eb243c73d9a264f03b8567b1fc40fbfa39ecc01f76bfff6bebd9ee477514ec8773a695dee503cbdf265694f477c520fbab2978052bfc87648fb4515440d096392197a5258116ca40d2e0ef33b673c49ed1772a8af1ab3dc90793a43e26a5fb40032210ed60469e80492586a298bcf212df8718cdf3818052812e62f7afb958902bff8c1901c92499988d5c2e1e95a59f3896ce126fde88b7554ab6e481f6ed6180ed2782fd3b23769610dc54957c253661801be1e93c43c125d67d24908f04e9e36270b94358940365021b761604cf76d5659af793f83b6defa9806e64384a5cae731e66fa9bf6280c909d73ff679a25f479a93ce73c8c6114a140b85</SIGNED_MSG>
  </INFO>
  <TRANSRET>
    <RET_CODE>0000</RET_CODE>
    <SETTLE_DAY>20130821</SETTLE_DAY>
  </TRANSRET>
</AIPG>请问大神，$result变量里是上面的xml，php怎么获取$result里的两个RET_CODE 节点值

Answer 1

$str = <<<TEXT
<?xml version="1.0" encoding="GBK"?><AIPG>
  <INFO>
    <TRX_CODE>100014</TRX_CODE>
    <VERSION>03</VERSION>
    <DATA_TYPE>2</DATA_TYPE>
    <REQ_SN>1377051780610</REQ_SN>
    <RET_CODE>0000</RET_CODE>
    <SIGNED_MSG>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</SIGNED_MSG>
  </INFO>
  <TRANSRET>
    <RET_CODE>0001</RET_CODE>
    <SETTLE_DAY>20130821</SETTLE_DAY>
  </TRANSRET>
</AIPG>
TEXT;
 
$xml = simplexml_load_string($str);
var_dump($xml);
echo '<br/>';
echo $xml->INFO->RET_CODE;echo '<br/>';
echo $xml->TRANSRET->RET_CODE;
echo '<br/>';

Answer 2

$str = <<<TEXT
<?xml version="1.0" encoding="GBK"?><AIPG>
  <INFO>
    <TRX_CODE>100014</TRX_CODE>
    <VERSION>03</VERSION>
    <DATA_TYPE>2</DATA_TYPE>
    <REQ_SN>1377051780610</REQ_SN>
    <RET_CODE>0000</RET_CODE>
    <SIGNED_MSG>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</SIGNED_MSG>
  </INFO>
  <TRANSRET>
    <RET_CODE>0001</RET_CODE>
    <SETTLE_DAY>20130821</SETTLE_DAY>
  </TRANSRET>
</AIPG>
TEXT;
 
$xml = simplexml_load_string($str);
var_dump($xml);
echo '<br/>';
echo $xml->INFO->RET_CODE;echo '<br/>';
echo $xml->TRANSRET->RET_CODE;
echo '<br/>';

Answer 3

 xml是在$result变量里，"<<<TEXT "  这个要怎么拼接上去？？？