dynamic associative array?

Question

I have array returned

$header_html = array(1=>array('width'=>40,
                               'sort_case'=>23,
                               'title'=>'AxA'),
                      2=>array('width'=>50,
                               'sort_case'=>7,
                               'title'=>'B2B'),
                      3=>array('width'=>100,
                               'sort_case'=>12,
                               'title'=>'C12')
                      );

I want to get new array that depend on $header_array=array('AxA','B2B','C12')

for examples:

 if have $header_array=array('C12','B2B','AxA').

the new $header_html will be:

$header_html = array(
                      1=>array('width'=>100,
                               'sort_case'=>12,
                               'title'=>'C12'),                         
                      2=>array('width'=>50,
                               'sort_case'=>7,
                               'title'=>'B2B'),
                      3=>array('width'=>40,
                               'sort_case'=>23,
                               'title'=>'AxA')

                      );

and so on...

Anybody know how to do this?

Answer 1

You can sort the array with a custom comparison function using usort :

function cmp($a, $b) {
  // Sort via $a['title'] and $b['title']
}

usort($header_html, 'cmp');

The trick is coming up with a comparison function that does what you want. To simply sort backwards by title, you could use:

function cmp($a, $b) {
  if ($a['title'] == $b['title'])
    return 0;

  // usually return -1 if $a < $b, but we're sorting backwards 
  return ($a['title'] < $b['title'] ? 1 : -1;
}

Answer 2

In PHP 5.3, you can easily do this with a functor and usort.

class MyComparator {
  protected $order = array();

  public function __construct() {
    $values = func_get_args();
    $i = 0;
    foreach($values as $v) {
      $this->order[$v] = $i;
      $i++;
    }
  }

  public function __invoke($a, $b) {
    $vala = isset($this->order[$a['title']]) ?
      $this->order[$a['title']] : count($this->order);
    $valb = isset($this->order[$b['title']]) ?
      $this->order[$b['title']] : count($this->order);
    if($vala == $valb) return 0;
    return $vala < $valb ? -1 : 1;
  }
}

You can use it like that:

$sorter = new MyComparator('CCC', 'AAA', 'BBB');
usort($header_html, $sorter);

Answer 3

You need a user-defined sort so you can access individual fields of the elements to sort:

function mysort($a, $b)
{
  global $header_array;
  $pos1 = array_search($a["title"], $header_array);
  $pos2 = array_search($b["title"], $header_array);
  if ($pos1 == $pos2) { return 0; }
  return $pos1 < $pos2 ? -1 : 1;
}

$header_array = array("CCC", "BBB", "AAA");
usort($header_html, "mysort");

print_r($header_array);

note: usort() returns true on success or false on failure; it does not return the resorted array.

Answer 4

It sounds like you want a function to return the array elements in the order you specify in $header_array . If so, here's a stab:

function header_resort($header_array, $header_html) {
    foreach($header_array as $i => $val) {
        foreach($header_html as $obj) {
            if( $obj->title == $val )
                $header_html_new[$i] = $obj;
        }
    }
    return $header_html_new;
}