PHP Array Goup using date with multiple keys and assign Sum of keys

I'm wring a PHP script to group some payment info using date. part of original array is like this.

 array(50) {
  [0]=>
  array(2) {
    ["Datum"]=>
    string(10) "2016-07-07"
    ["C"]=>
    int(1)
  }
  [1]=>
  array(2) {
    ["Datum"]=>
    string(10) "2016-07-07"
    ["C"]=>
    int(1)
  }
  [2]=>
  array(2) {
    ["Datum"]=>
    string(10) "2016-07-07"
    ["Paypal"]=>
    int(1)
  }
  [3]=>
  array(2) {
    ["Datum"]=>
    string(10) "2016-07-07"
    ["Bank"]=>
    int(1)
  }
  [4]=>
  array(2) {
    ["Datum"]=>
    string(10) "2016-07-12"
    ["C"]=>
    int(1)
  }
  [5]=>
  array(2) {
    ["Datum"]=>
    string(10) "2016-06-13"
    ["C"]=>
    int(1)
  }
  [6]=>
  array(2) {
    ["Datum"]=>
    string(10) "2016-06-13"
    ["C"]=>
    int(1)
  }
  [7]=>
  array(2) {
    ["Datum"]=>
    string(10) "2016-06-13"
    ["Afterpay"]=>
    int(1)
  }
  [8]=>
  array(2) {
    ["Datum"]=>
    string(10) "2016-06-13"
    ["C"]=>
    int(1)
  }
  [9]=>
  array(2) {
    ["Datum"]=>
    string(10) "2016-06-13"
    ["C"]=>
    int(1)
  }
  [10]=>
  array(2) {
    ["Datum"]=>
    string(10) "2016-06-12"
    ["C"]=>
    int(1)
  }
  [11]=>
  array(2) {
    ["Datum"]=>
    string(10) "2016-06-13"
    ["C"]=>
    int(1)
  }
  [12]=>
  array(2) {
    ["Datum"]=>
    string(10) "2016-06-13"
    ["C"]=>
    int(1)
  }
  [13]=>
  array(2) {
    ["Datum"]=>
    string(10) "2016-06-13"
    ["C"]=>
    int(1)
  }
  [14]=>
  array(2) {
    ["Datum"]=>
    string(10) "2016-06-13"
    ["C"]=>
    int(1)
  }
  [15]=>
  array(2) {
    ["Datum"]=>
    string(10) "2016-06-13"
    ["C"]=>
    int(1)
  }
  [16]=>
  array(2) {
    ["Datum"]=>
    string(10) "2016-06-13"
    ["C"]=>
    int(1)
  }
  [17]=>
  array(2) {
    ["Datum"]=>
    string(10) "2016-06-13"
    ["C"]=>
    int(1)
  }
  [18]=>
  array(2) {
    ["Datum"]=>
    string(10) "2016-06-14"
    ["Afterpay"]=>
    int(1)
  }
  [19]=>
  array(2) {
    ["Datum"]=>
    string(10) "2016-06-14"
    ["C"]=>
    int(1)
  }
    }

I wrote some codes to group those by date. here is my code

//$shipment - this is the original array
    $array1 = array('C' => null, 'afterpay' => null,'paypal' => null, 'Bank' => null, 'Ideal' => null);
    $array2 = array();

    array_walk($shipment, function ($v) use (&$array2, $array1) {
        $a = $v['Datum'];
        if (!isset($array2[$a])) {
            $array2[$a] = $array1;
        }
        unset($v['Datum']);
        $array2[$a] = array_merge($array2[$a], $v);
    });

Output after grouping

Array
(
    [2016-07-07] => Array
        (
            [C] => 1
            [afterpay] => 
            [paypal] => 
            [Bank] => 1
            [Ideal] => 
            [Paypal] => 1
        )

    [2016-07-12] => Array
        (
            [C] => 1
            [afterpay] => 
            [paypal] => 
            [Bank] => 
            [Ideal] => 
        )

    [2016-06-13] => Array
        (
            [C] => 1
            [afterpay] => 
            [paypal] => 
            [Bank] => 
            [Ideal] => 
            [Afterpay] => 1
        )

    [2016-06-12] => Array
        (
            [C] => 1
            [afterpay] => 
            [paypal] => 
            [Bank] => 
            [Ideal] => 
        )

    [2016-06-14] => Array
        (
            [C] => 1
            [afterpay] => 
            [paypal] => 
            [Bank] => 
            [Ideal] => 
            [Afterpay] => 1
        )
)

but it's difficult me to find a way to count the payment method numbers and assign it

Example for 2016-07-07 array should be C= 2,Paypal = 1, Bank = 1

[2016-07-07] => Array
            (
                [C] => 2
                [afterpay] => 
                [paypal] => 
                [Bank] => 1
                [Ideal] => 
                [Paypal] => 1
            )

can someone help me to add some code for get sum of payment methods and assign, thanks a lot

This happens because array_merge override the data if 2 keys are the same - what you need is to add all fields.

First, change $array1 with init field as 0 instead of null.

Second, in your array_walk, replace $array2[$a] = array_merge($array2[$a], $v); with:

foreach($v as $k => $v)
    $array2[$a][$k] += $v;

This way you will add up each category