php Cannot call the function for array_map - php

Question

I am using php 5.2.10 i want to do the array_map on the array and i created a function for array mapping
function get_result(){
$result = mysql_query("Select * from table");
while($cr = mysql_fetch_array($result)){
$b = array_map(`calc`,$cr);
$rr_id = $cr['batch_id'].$cr['seq_id'];
$mqrrid = '999'.$rr_id;
$question_id = $cr['question_id'];
foreach ($b as $k => $v){
if(preg_match('{^Item \d+$}',$k)){
$new_insert[] = array(
'r_id'=>$mqrrid,
'q_id' =>$q_id,
'c_id' =>$k,
'rank'=>$v
);
}
}
}
}
function calc($n){
foreach($n as $m=> &$x) {
if (preg_match('{^Item \d+$}', $m)) {
if($x == null){
$x = $x;
}else {
$x = $x - 1;
}
}
}
return $n;
}
I don't know why I cannot call the function calc in array_map.....I cannot figure out the reason.....
Can anyone help me ?
original array :( actually the output after the array_map(calc,$cr) are same as follow)
array(23) {
["batch_id"]=>
string(1) "1"
["seq_id"]=>
string(1) "1"
["question_id"]=>
string(4) "2086"
["Item 1"]=>
string(1) "1"
["Item 2"]=>
string(1) "2"
["Item 3"]=>
string(1) "3"
["Item 4"]=>
string(1) "4"
["Item 5"]=>
string(1) "5"
["Item 6"]=>
NULL
what i need is : (minus the value of Item 1 to 6 by 1, if its null just leave it ~)
array(23) {
["batch_id"]=>
string(1) "1"
["seq_id"]=>
string(1) "1"
["q_id"]=>
string(4) "2086"
["Item 1"]=>
string(1) "0"
["Item 2"]=>
string(1) "1"
["Item 3"]=>
string(1) "2"
["Item 4"]=>
string(1) "3"
["Item 5"]=>
string(1) "4"
["Item 6"]=>
NULL
Finally, the result will become like this:(example of Item 1 and Item 6)
array(4) {
["r_id"]=>
string(5) "99911"
["q_id"]=>
string(4) "2086"
["c_id"]=>
string(6) "Item 1"
["rank"]=>
string(1) "0"
}
array(4) {
["r_id"]=>
string(5) "99916"
["q_id"]=>
string(4) "2086"
["c_id"]=>
string(6) "Item 6"
["rank"]=>
string(4) NULL
}

Answer 1

calc should be global, otherwise it cannot be found. Also, you should pass a string (no ` but rather enclose in ' or ").
Additionally, in general (if you used PHP 5.3), it is better to pass a function reference to the array_map function, instead of a string:
$func = function calc() { ... }
array_map($func, $cr);

Answer 2

I think you don't have to prepare the function for array_map.
function get_result($link_identifier = NULL) {
$result = mysql_query('Select * from table', $link_identifier);
$new = array();
while ($rows = mysql_fetch_assoc($result)) {
$r_id = '999' . $rows['batch_id'] . $rows['seq_id'];
foreach ($rows as $k => $v) {
if ($v !== null && preg_match('#^Item \\d+$#', $k)) {
$v = (string)((int)$v + 1);
}
$new[] = array(
'r_id' => $r_id,
'q_id' => $rows['question_id'],
'c_id' => $k,
'rank' => $v,
);
}
}
return $new;
}