PHP数组操作问题

$a = array("1"=>"123","2"=>"1234","3"=>"1334");$b = array("1"=>"123","2"=>"1230");$c = array();foreach($a as $k=>$v) {  if(isset($b[$k])) {    if($b[$k] == $v) continue; //相同的不保存    $c[$k] = max($b[$k], $v); //不相同保留大的  }else $c[$k] = 'delete';}print_r($c);

$a = array("1"=>"123","2"=>"1234","3"=>"1334");$b = array("1"=>"123","2"=>"1230");$c = array();foreach($a as $key=>$val){if(isset($b[$key])){if($val!=$b[$key]){$c[$key] = $val>$b[$key]? $val : $b[$key];}}else{$c[$key] = 'delete';}}print_r($c);