Array format Conversion in PHP - php

Question

I have got an array which looks like the following:
Array ( [0] => Array ( [id] => 0 ) [1] => Array ( [id] => 0 ) [2] => Array ( [id] => 0 ) [3] => Array ( [id] => 0 ) [4] => Array ( [id] => 0 ) [5] => Array ( [id] => 0 ) [6] => Array ( [id] => 0 ) [7] => Array ( [id] => 0 ) [8] => Array ( [id] => 0 ) [9] => Array ( [id] => 0 ) [10] => Array ( [id] => 0 ) [11] => Array ( [id] => 4 ) [12] => Array ( [id] => 1 ) [13] => Array ( [id] => 2 ) [14] => Array ( [id] => 0 ) [15] => Array ( [id] => 0 ) [16] => Array ( [id] => 5 ) [17] => Array ( [id] => 1 ) )
and I would like to convert it into the following format:
[0,0,0,0,0,0,0,0,0,0,0,4,1,2,0,0,5,1]
How can I achieve this conversion using php?
All the help is appreciated.

Answer 1

PHP >= 5.5.0 needed for array_column() or use the PHP Implementation of array_column():
$result = array_column($array, 'id');

Answer 2

Simplest way: (assuming that you want it to actually output the string [5,6,...,2]
<?php
$ids=array();
foreach($yourArray as $k=>$v){
$ids[] = $v['id'];
}
$resultCsv = implode(',', $ids);
$result = '['.$resultCsv.']';
echo $result
?>

Answer 3

You can use array_map or array_walk:
With array_map:
$new = array_map(function ($value) { return $value['id']; }, $theArray);
print_r($new);
With array_walk:
array_walk($theArray, function (&$value, $key) { $value = $value['id']; };
print_r($theArray);
The main differences between these is that array_map produces a completely new array, and you dont get the key passed to the callback function. array_walk on the other hand works on the array by reference and the callback also gets the key.
Now its unclear to me whether you wanted the array restructured (as i provided solutions for) or if you want it in a specific string format like the [0,1,2,3,...] you provided. If you did want it in a string format all you need to do now is call json_encode on it:
// note if you used array_map pass the variable that holds the result of the call
// (in my example that would be $new); If you used array_walk then pass the same array
// you supplied as the argument to the call (in my exmaple that would be $theArray)
$arrString = json_encode($theArray);

Answer 4

You can process every member of the array and append every currently processed sub-array's member "id" to a new array:
<?php
// code
foreach $array as $member {
$newarray[]=$member["id"];
}
// code
?>