PHP中多维数组的求和值

Supposing I have this array in PHP:

Array
(
    [0] => Array
        (
            [name] => Banana
            [quantity] => 124
        )
    [1] => Array
        (
            [name] => Cherry
            [quantity] => 24
        )
    [2] => Array
        (
            [name] => Apple
            [quantity] => 224
        )

)

How can I sum the number with the key quantity ?

Thanks.

Please, always share with us what you have tried.

It help us a lot.

You can use:

$arr = [['name' => "Banana", 'quantity' => 124], ['name' => "Cherry", 'quantity' => 24], ['name' => "Apple", 'quantity' => 224]];

$sum = 0;
foreach ($arr as $item) {
    $sum += $item['quantity'];
}

Or (PHP 5.5+):

$sum = array_sum(array_column($arr, 'quantity'));

/*
    Receives a Multidemensional Array (Matrix) and returns the sum of quantity.
    Returns -1 on fail.
*/
function SumKeyOfArray($Matrix)
{
    if(!empty($Matrix))
    {
        $sum = 0;       
        foreach($Matrix as $array)
        {
            if(isset($array['quantity']))
                $sum = $sum + $array['quantity'];
        }
        return $sum;
    }
    return -1;
}

Another option is to use the reduce function:

$arr= [['name' => "Banana", 'quantity' => 124], ['name' => "Cherry", 'quantity' => 24], ['name' => "Apple", 'quantity' => 224]];

echo array_reduce($arr, function($sum, $elem) {
    return $sum += $elem["quantity"];
});