PHP數組比較問題

$ar1=array(array('id'=>1,"name"=>"張1","sign"=>""),array('id'=>2,"name"=>"張2","sign"=>""),array('id'=>5,"name"=>"張5","sign"=>""));        $ar2=array(array('id'=>1,"name"=>"張1"),array('id'=>2,"name"=>"張2"));

如果ar2的id與ar1的id相同，那麼ar1的sign則複製給1，否則不賦值，怎麼解決？

回複討論(解決方案)

$ar1=array(array('id'=>1,"name"=>"張1","sign"=>""),array('id'=>2,"name"=>"張2","sign"=>""),array('id'=>5,"name"=>"張5","sign"=>""));$ar2=array(array('id'=>1,"name"=>"張1"),array('id'=>2,"name"=>"張2"));//先將 $ar2 規格化一下foreach($ar2 as $v) $r[$v['id']] = $v;$ar2 = $r;//接下來就簡單了foreach($ar1 as &$v) {  if(isset($ar2[$v['id']])) $v['sign'] = 1;}print_r($ar1);

Array(    [0] => Array        (            [id] => 1            [name] => 張1            [sign] => 1        )    [1] => Array        (            [id] => 2            [name] => 張2            [sign] => 1        )    [2] => Array        (            [id] => 5            [name] => 張5            [sign] =>         ))

