array_values

Remember, array_values() will ignore your beautiful numeric indexes, it will renumber them according tho the 'foreach' ordering:

<?php
$a = array(
 3 => 11,
 1 => 22,
 2 => 33,
);
$a[0] = 44;

print_r( array_values( $a ));
==>
Array(
  [0] => 11
  [1] => 22
  [2] => 33
  [3] => 44
)
?>

Just a warning that re-indexing an array by array_values() may cause you to reach the memory limit unexpectly.

For example, if your PHP momory_limits is 8MB,
 and says there's a BIG array $bigArray which allocate 5MB of memory.

Doing this will cause PHP exceeds the momory limits:

<?php
  $bigArray = array_values( $bigArray );
?>

It's because array_values() does not re-index $bigArray directly,
it just re-index it into another array, and assign to itself later.

This is another way to get value from a multidimensional array, but for versions of php >= 5.3.x
<?php
/**
 * Get all values from specific key in a multidimensional array
 *
 * @param $key string
 * @param $arr array
 * @return null|string|array
 */
function array_value_recursive($key, array $arr){
    $val = array();
    array_walk_recursive($arr, function($v, $k) use($key, &$val){
        if($k == $key) array_push($val, $v);
    });
    return count($val) > 1 ? $val : array_pop($val);
}

$arr = array(
    'foo' => 'foo',
    'bar' => array(
        'baz' => 'baz',
        'candy' => 'candy',
        'vegetable' => array(
            'carrot' => 'carrot',
        )
    ),
    'vegetable' => array(
        'carrot' => 'carrot2',
    ),
    'fruits' => 'fruits',
);

var_dump(array_value_recursive('carrot', $arr)); // array(2) { [0]=> string(6) "carrot" [1]=> string(7) "carrot2" }
var_dump(array_value_recursive('apple', $arr)); // null
var_dump(array_value_recursive('baz', $arr)); // string(3) "baz"
var_dump(array_value_recursive('candy', $arr)); // string(5) "candy"
var_dump(array_value_recursive('pear', $arr)); // null
?>

Most of the array_flatten functions don't allow preservation of keys. Mine allows preserve, don't preserve, and preserve only strings (default).

<?
// recursively reduces deep arrays to single-dimensional arrays
// $preserve_keys: (0=>never, 1=>strings, 2=>always)
function array_flatten($array, $preserve_keys = 1, &$newArray = Array()) {
  foreach ($array as $key => $child) {
    if (is_array($child)) {
      $newArray =& array_flatten($child, $preserve_keys, $newArray);
    } elseif ($preserve_keys + is_string($key) > 1) {
      $newArray[$key] = $child;
    } else {
      $newArray[] = $child;
    }
  }
  return $newArray;
}

// Tests

$array = Array(
  'A' => Array(
    1 => 'foo',
    2 => Array(
      'a' => 'bar'
    )
  ),
  'B' => 'baz'
);

echo 'var_dump($array);'."\n";
var_dump($array);
echo 'var_dump(array_flatten($array, 0));'."\n";
var_dump(array_flatten($array, 0));
echo 'var_dump(array_flatten($array, 1));'."\n";
var_dump(array_flatten($array, 1));
echo 'var_dump(array_flatten($array, 2));'."\n";
var_dump(array_flatten($array, 2));
?>

If you are looking for a way to count the total number of times a specific value appears in array, use this function:

<?php
function array_value_count ($match, $array)
{
    $count = 0;
    
    foreach ($array as $key => $value)
    {
        if ($value == $match)
        {
            $count++;
        }
    }
    
    return $count;
}
?>

This should really be a native function of PHP.

<?php 
/**
   flatten an arbitrarily deep multidimensional array 
   into a list of its scalar values
   (may be inefficient for large structures)
   (will infinite recurse on self-referential structures)
   (could be extended to handle objects)
*/
function array_values_recursive($ary)
{
   $lst = array();
   foreach( array_keys($ary) as $k ){
      $v = $ary[$k];
      if (is_scalar($v)) {
         $lst[] = $v;
      } elseif (is_array($v)) {
         $lst = array_merge( $lst,
            array_values_recursive($v)
         );
      }
   }
   return $lst;
}
?>

code till dawn!  -mark meves!