php array recursive sum

Question

up vote 0 down vote favorite

Hello. 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.

edited Sep 23 at 12:08

Paul Dixon
38.8k146106

asked Sep 23 at 11:47

Alexander.Plutov
85818

100% accept rate

Medoo: stackoverflow.com/questions/3777134/…, stackoverflow.com/questions/3776798/php-array-recursion, ... – Wernight Sep 23 at 11:57

3

The sum of those values should actually be 230 rather than 240 – Mark Baker Sep 23 at 12:06

1

:) I have seen that array before – xtofl Sep 23 at 12:23

salathe · Answer 1 · 2010-09-24 08:50:37Z

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
    )
);

fredley · Answer 2 · 2010-09-23 11:50:40Z

up vote 5 down vote

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;
}

answered Sep 23 at 11:50

fredley
2,18712

1

+1! I hate passing function names as string as required for array_reduce(), etc. Nice and clean solution! – elusive Sep 23 at 12:00

3

@elusive: in PHP5.3 you can just pass anonymous functions (like javascript tends to do), maybe that's less creepy to you: $arr = range(1,40); var_dump(array_reduce($arr,function($v,$k){return $v+$k;})); – Wrikken Sep 23 at 12:05

@Wrikken: Thats right, but you cannot assume that PHP 5.3 is already running everywhere. AFAIK, 5.3 will ship with the next release of debian at the earliest. fredleys solution works nicely with currently used versions of PHP and i consider it less ugly than the array_reduce() method. – elusive Sep 23 at 12:10

Afaik, 5.3.2 is in the testing branch, so in Debian terms that will be 'soonish', and I'm not disputing this is a nice solution (+1 'ed it), just reacted to your 'I don't like to pass function names as string' with some info you might be happy with in future in case you didn't know already ;) – Wrikken Sep 23 at 13:01

@Wrikken: Yes, thanks ;) – elusive Sep 23 at 13:11

Ali Sattari · Answer 3 · 2010-09-23 11:55:27Z

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");

stereofrog · Answer 4 · 2010-09-23 12:05:28Z

up vote 2 down vote

based on @Ali Sattari answer

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

answered Sep 23 at 12:05

stereofrog
13.3k1521

Mark Baker · Answer 5 · 2010-09-23 11:54:43Z

up vote 1 down vote

$sum = 0;

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

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

answered Sep 23 at 11:54

Mark Baker
9,627418

	Works as long as there are nothing other than arrays and numbers with the key `pv`. – fredley Sep 23 at 11:55
	@fredley - if the OP has additional criteria (eg test for booleans, etc) they can easily be added to the sumArray callback function – Mark Baker Sep 23 at 11:57

Auirio · Answer 6 · 2010-09-23 12:15:55Z

$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);

RobertPitt · Answer 7 · 2010-09-23 12:21:59Z

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.

Alexander.Plutov · Answer 8 · 2010-09-23 11:50:07Z

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;
}

php array recursive sum

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