count from several multidimensional arrays

Question

hi all,

i have foreach, which generate following arrays:

==== array 1 ====
array
  0 => 
    array
      'tag' => string 'daf' (length=3)
  1 => 
    array
      'tag' => string 'daa' (length=3)
  2 => 
    array
      'tag' => string 'daf' (length=3)
  3 => 
    array
      'tag' => string 'daaa' (length=4)
  4 => 
    array
      'tag' => string 'daf' (length=3)
  5 => 
    array
      'tag' => string 'daa' (length=3)
  6 => 
    array
      'tag' => string 'daf' (length=3)
  7 => 
    array
      'tag' => string 'daf' (length=3)
  8 => 
    array
      'tag' => string 'daf' (length=3)
  9 => 
    array
      'tag' => string 'abd' (length=3)
  10 => 
    array
      'tag' => string 'abdaa' (length=5)
  11 => 
    array
      'tag' => string 'abda' (length=4)

==== array 2 ====    
array
  0 => 
    array
      'tag' => string 'daf' (length=3)
  1 => 
    array
      'tag' => string 'test1' (length=5)

As output i want to get something like:

array
  'daf' => '7'
  'daa' => '2'
  'daaa' => '1'
  'abd' => '1'
  'abdaa' => '1'
  'abda' => '1'
  'test1' => '1'

The value of the new array is the count of the element from all aray generatet from the loop. array_count_values() doesn't work here...any suggestions, how to solve the problem?

Answer 1

Something a bit like this should work:

$result = array();
foreach (array_merge($array1, $array2) as $item) {
    $name = $item['tag'];   
    if (!isset($result[$name])) {
        $result[$name] = 0;   
    } 

    $result[$name]++;
}

Answer 2

Did not notice it was 2 dimensional array.

Here is another code.

var_export(
    array_count_values(
     call_user_func_array('array_merge', array_merge($array1, $array2))
    )
);

Answer 3

Let's make some use of the Standard PHP Library (SPL).
You can "flatten" an array with an RecursiveArrayIterator and RecursiveIteratorIterator. As a result you get an iterator that visits each leaf of your n-dimensional array and still let's you access the actual key of the element. In the next step concat both RecursiveIteratorIterators with an AppendIterator acting like a single interator that visits each element in all of its inner (appended) iterators.

$ai = new AppendIterator;
$ai->append(new RecursiveIteratorIterator(new RecursiveArrayIterator($array1)));
$ai->append(new RecursiveIteratorIterator(new RecursiveArrayIterator($array2)));
$counters = array();
foreach($ai as $key=>$value) {
  if ( 'tag'===$key ) {
    // @ because I don't care whether this array element exists beforehand or not.
    // $value has to be something that can be used as an array key (strings in this case)
    @$counters[$value] += 1;
  }
}

If you want you can even use a FilterIterator instead of the if('tag'===$key). But imho this doesn't increase the readability/value of the code ;-)