如何在数组中进行计算

I have an array :

Array
(
    [0] => Array
  (
      [batch_id] => 1
      [seq_id] => 1
      [q_id] => 2046
      [a1] => 0
      [a2] => 1
      [a3] => 2
      [a4] => 3
      [a5] => 4

  )
)

I need to minus the value of a1-a5 by 1

desire result(e.g. a1):

 array(4) {
["w_id"]=>
string(5) "99911"
["q_id"]=>
string(4) "2046"
["c_id"]=>
string(6) "a1"
["rank"]=>
int(1) "-1"
}

My code is as follow:

$result = mysql_query("Select * from table_1");     
while($cr = mysql_fetch_array($result)){    
    $rr_id = $cr['batch_id'].$cr['seq_id'];
    $rid = '999'.$rr_id;
          $q_id = $cr['q_id'];
     foreach ($cr as $k => $v){
  if(preg_match('{^a\d+$}',$k)){
    $new_insert[] = array(
        'w_id'=>$rid,
        'q_id' =>$q_id,
        'c_id' =>$k,
        'rank'=>$v-1
);
     }
  }

However, the result of rank becomes

array(4) {
["w_id"]=>
string(5) "99911"
["q_id"]=>
string(4) "2046"
["c_id"]=>
string(6) "a1"
["rank"]=>
int(0)
}

Cannot show the value of rank

Any problem with my code??Can someone answer my question thank you very much

You can use :

$data = array_map(function ($v) {
    foreach($v as $k => &$x) {
        if (preg_match('{^a\d+$}', $k)) {
            $x = $x - 1;
        }
    }
    return $v;
}, $data);

print_r($data);

Live Demo

Just use loop and pre decrementation

foreach($cr as $k=>&$v)
{
 --$v['a1'];--$v['a2'];--$v['a3'];--$v['a4'];--$v['a5'];
}

print_r($cr);

preg_match('{^Item \d+$}',$k)

You've got wrong pattern inside preg_match (keys you are looking for are 'a1','a2'... not 'item 1', 'item 2'...), just use this one:

preg_match('{^a\d+$}',$k)

I use $cr as your array.

$cr[] = array("batch_id"=>1, "seq_id"=>1, "q_id"=>'2046', "a1"=>1,"a2"=>1,"a3"=>1,"a4"=>1,"a5"=>1);

foreach($cr as $k=>&$v){
  $v['a1'] = $v['a1'] - 1;
  $v['a2'] = $v['a2'] - 1;
  $v['a3'] = $v['a3'] - 1;
  $v['a4'] = $v['a4'] - 1;
  $v['a5'] = $v['a5'] - 1;
}
print_r($cr);