php 基础问题二维数组求和 ！
数组：
$a = array(array("a"=>"aa","a1"=>1,"a2"=>1),array("a"=>"bb","a1"=>2,"a2"=>2),array("a"=>"cc","a1"=>3,"a2"=>3),array("a"=>"aa","a1"=>1,"a2"=>1),array("a"=>"bb","a1"=>5,"a2"=>5))
第一个键值相同的元素 求和
结果
$r = array(array("a"=>"aa","a1"=>2,"a2"=>2),array("a"=>"bb","a1"=>7,"a2"=>7),array("a"=>"cc","a1"=>3,"a2"=>3));
------解决方案--------------------
$a = array(<br /> array("a" => "aa", "a1" => 1, "a2" => 1),<br /> array("a" => "bb", "a1" => 2, "a2" => 2),<br /> array("a" => "cc", "a1" => 3, "a2" => 3),<br /> array("a" => "aa", "a1" => 1, "a2" => 1),<br /> array("a" => "bb", "a1" => 5, "a2" => 5),<br />);<br />$res = array();<br />foreach($a as $r) {<br /> if(! isset($res[$r['a']])) $res[$r['a']] = $r;<br /> else {<br /> $res[$r['a']]['a1'] += $r['a1'];<br /> $res[$r['a']]['a2'] += $r['a2'];<br /> }<br />}<br />print_r(array_values($res));Array<br />(<br /> [0] => Array<br /> (<br /> [a] => aa<br /> [a1] => 2<br /> [a2] => 2<br /> )<br /><br /> [1] => Array<br /> (<br /> [a] => bb<br /> [a1] => 7<br /> [a2] => 7<br /> )<br /><br /> [2] => Array<br /> (<br /> [a] => cc<br /> [a1] => 3<br /> [a2] => 3<br /> )<br /><br />)<br /><br />
