usort(), $GLOBALS, global keyword, HELP!

[ppowell]

I am having to sort an array of objects by an arbitrary object field name that you are not going to know in advance, therefore, I cannot name the sorting function accordingly nor reference the object accordingly:

class ResizeView extends View {

 function displayHTML() {

  $field = $safe->getField();
  global $field;
  $safe = null;
  if (!$field) $field = 'image_name'; // DEFAULT FIELD NAME

  usort($imageArray, array($this, 'field_name_sort'));
 }


 function field_name_sort(&$a, $b) {
   global $field;
   if ($a[???]->$field === $b[???]->$field) return 0;
   return (strcmp(strtolower($a[???]->$field), strtolower($b->$field));
 }

}

I am stuck. I can't pass the value of $field, which is required for the sorting to be dynamically possible according to the value of $field within the array of objects who happens to have an object property named the value of $field. How then can I sort my array of objects? The PHP manual offers no help for this at all since it doesn't involve anything LIKE this!

Thanx
Phil

[flatpooks]

variable variables?

use $$var_name...

[ahundiak]

// This:
function field_name_sort(&$a, $b) {
   global $field;
   if ($a[???]->$field === $b[???]->$field) return 0;
   return (strcmp(strtolower($a[???]->$field), strtolower($b->$field));
 } 
// shoud be something like:
function field_name_sort($a, $b) {
   global $field;
   return strcmp(strtolower($a->$field), strtolower($b->$field));
 } 

And make sure $imageArray is in scope when usort is called.

[ppowell]

Actually I did one better than that..

class Sorter {

  function Sorter(&$imageArray, $fieldName) { // CONSTRUCTOR
   $this->imageArray =& $imageArray;
   $this->fieldName = $fieldName;
  }

  function isValidObjectArray() {  // BOOLEAN METHOD
   if (!is_array($this->imageArray)) return false;
   if (!is_array(array_keys(@get_object_vars($this->imageArray)))) return false;
   return true;
  }

  function fieldNameSort(&$a, &$b) {
   if (strtolower($a->{$this->fieldName}) === strtolower($b->{$this->fieldName})) return 0;
   return strcmp(strtolower($a->{$this->fieldName}), strtolower($b->{$this->fieldName}));

   }

}

if ($field) $field = 'image_name';
$sorter =& new Sorter($imageArray, $field);
if ($sorter->isValidObjectArray()) usort($imageArray, array($sorter, 'fieldNameSort'));
$sorter = null;

Woo hoo! Thanx

Phil