PHP 数组,该如何处理

$a = array(<br />  'pid=2',<br />  'action=save',<br />  '9=a',<br />  '10=a',<br />  '14=a',<br />  '20=a',<br />  '15=a',<br />  '15=b',<br />  '21=a',<br />  '21=b',<br />  '16=c',<br />  '16=d',<br />  '19=c',<br />  '19=d',<br />  '17=we',<br />  '22=keywork',<br />  '18=you',<br />  '23=thanks',<br />);<br />foreach($a as $v) list($b[$v][],$v) = array_reverse(explode('=', $v));<br />array_walk($b, create_function('&$v,$k', '$v="$k=".join("",$v);'));<br />print_r(array_values($b));

Array<br />(<br />    [0] => pid=2<br />    [1] => action=save<br />    [2] => 9=a<br />    [3] => 10=a<br />    [4] => 14=a<br />    [5] => 20=a<br />    [6] => 15=ab<br />    [7] => 21=ab<br />    [8] => 16=cd<br />    [9] => 19=cd<br />    [10] => 17=we<br />    [11] => 22=keywork<br />    [12] => 18=you<br />    [13] => 23=thanks<br />)<br /><br />