php array recursive sum

问题:

I have an array like this:

Array
(
    [1000] => Array
        (
            [pv] => 36
        )

    [1101] => Array
        (
            [1102] => Array
                (
                    [pv] => 92
                )

            [pv] => 38
        )

    [pv] => 64
)

How I can find the sum of all array elements with key 'pv', regardless of the depth at which they appear.

For this example the result will 36+92+38+64 = 240

Thanks for help.

回答1:

Another alternative:

$sum = 0;
$array_obj = new RecursiveIteratorIterator(new RecursiveArrayIterator($array));
foreach($array_obj as $key => $value) {
    if($key == 'pv')
        $sum += $value;
}
echo $sum;

Update: Just thought I'd mention that this method uses the PHP SPL Iterators.

---

Salathe Edit:

A simple (relatively) way to filter the keys and to sum the values (without writing a custom Iterator) would be to do some filtering with a RegexIterator, convert the resulting iterator into an array and use the handy array_sum function on it. This is purely an academic exercise and I certainly wouldn't advocate it as the best way to achieve this... however, it is just one line-of-code. :)

$sum = array_sum(
    iterator_to_array(
        new RegexIterator(
            new RecursiveIteratorIterator(
                new RecursiveArrayIterator($array)
            ),
            '/^pv$/D',
            RegexIterator::MATCH,
            RegexIterator::USE_KEY
        ),
        false
    )
);

回答2:

function addPV($array){
  $sum = 0;
  foreach($array as $key => $a){
    if (is_array($a)){
       $sum += addPV($a);
    }else if($key == 'pv') {
       $sum += $a;
    }
  }
  return $sum;
}

回答3:

based on @Ali Sattari answer

function sum($v, $w) {
    return $v + (is_array($w) ? 
        array_reduce($w, __FUNCTION__) : $w);
}

回答4:

you can use array_reduce or array_walk_recursive functions and a custom call back function of yourself:

function sum($v, $w)
{
    $v += $w;
    return $v;
}

$total = array_reduce($your_array, "sum");

回答5:

$sum = 0;

function sumArray($item, $key, &$sum)
{
    if ($key == 'pv')
       $sum += $item;
}

array_walk_recursive($array, 'sumArray',&$sum);
echo $sum;

回答6:

$array = array('1000'=> array('pv'=>36), array('1101' => array('pv'=>92)));

$total = 0;
foreach(new recursiveIteratorIterator( new recursiveArrayIterator($array)) as $sub)
{
 $total += (int)  $sub;
}
print_r($total);

回答7:

function SumRecursiveByKey($array,$key)
{
    $total = 0;
    foreach($array as $_key => $value)
    {
        if(is_array($value))
        {
            $total += SumRecursiveByKey($array,$key);
        }elseif($_key == $key)
        {
             $total += $value;
        }
    }
    return $total;
}

use like

$summed_items = SumRecursiveByKey($myArray,'pv');

This would give you more leeway in checking alternative keys a swell.

回答8:

private function calculateUserGv($userId) {
    $group = $this->arrayUnder($this->_user_tree, $userId);
    global $gv;
    $gv = 0;
    $gv    = $this->gvRecursive($group);
    return;
}

private function gvRecursive($group) {
    global $gv;
    foreach ($group as $key => $val) {
        if ($key == 'pv') {
            $gv += $group[$key];
        }
        else {
            $this->gvRecursive($val);
        }
    }
    return $gv;
}