有一个二维数组，小弟我想取出其中一个key的集合，并计算总和

<br />array( <br />        [0] => Array ( <br />		[id] => 5 <br />		[title] => 相宜本草八倍凝水霜50g 保湿补水滋润美白面霜乳液男女正品护肤品 <br />		[images] => uploadfile/goods/2015-01/1420774763.jpg <br />		[price] => 39.0 <br />		[num] => 1 <br />		[total] => 39 <br />		[wlmoney] => 0 <br />		[url] => http://localhost/dkyq/goods.php?id=12 ) <br />		<br />		<br />        [1] => Array ( <br />		[id] => 4 <br />		[title] => 美肤宝正品 水份源洁面膏洁面乳75ml 洗面奶清洁爽肤 补水保湿 <br />		[images] => uploadfile/goods/2015-01/1420773795.jpg <br />		[price] => 12.0 <br />		[num] => 1 <br />		[total] => 12 <br />		[wlmoney] => 0 <br />		[url] => http://localhost/dkyq/goods.php?id=11 <br />		) <br />);<br />

$ar = array (<br />  0 => array (<br />    'id' => '5',<br />    'title' => '相宜本草八倍凝水霜50g 保湿补水滋润美白面霜乳液男女正品护肤品',<br />    'images' => 'uploadfile/goods/2015-01/1420774763.jpg',<br />    'price' => '39.0',<br />    'num' => '1',<br />    'total' => '39',<br />    'wlmoney' => '0',<br />    'url' => 'http://localhost/dkyq/goods.php?id=12',<br />  ),<br />  1 => array (<br />    'id' => '4',<br />    'title' => '美肤宝正品 水份源洁面膏洁面乳75ml 洗面奶清洁爽肤 补水保湿',<br />    'images' => 'uploadfile/goods/2015-01/1420773795.jpg',<br />    'price' => '12.0',<br />    'num' => '1',<br />    'total' => '12',<br />    'wlmoney' => '0',<br />    'url' => 'http://localhost/dkyq/goods.php?id=11',<br />  ),<br />);<br /><br />$total = 0;<br />foreach($ar as $r) $total += $r['total'];<br />echo $total; //51

<br />$arr = array(<br />   array(<br />    'id' => '5',<br />    'title' => '相宜本草八倍凝水霜50g 保湿补水滋润美白面霜乳液男女正品护肤品',<br />    'images' => 'uploadfile/goods/2015-01/1420774763.jpg',<br />    'price' => '39.0',<br />    'num' => '1',<br />    'total' => '39',<br />    'wlmoney' => '0',<br />    'url' => 'http://localhost/dkyq/goods.php?id=12',<br />  ),<br />  array(<br />    'id' => '4',<br />    'title' => '美肤宝正品 水份源洁面膏洁面乳75ml 洗面奶清洁爽肤 补水保湿',<br />    'images' => 'uploadfile/goods/2015-01/1420773795.jpg',<br />    'price' => '12.0',<br />    'num' => '1',<br />    'total' => '12',<br />    'wlmoney' => '0',<br />    'url' => 'http://localhost/dkyq/goods.php?id=11',<br />  )<br />);<br />$total = 0;<br />foreach($arr as $v){<br />    $total += $v['total'];<br />}<br />echo $total;<br />