如何使用php獲取多維數組中相似值的鍵

Question

我正在使用PHP中的多維數組。 我想檢測相似值的存在，然后計算相似值的數量並輸出結果。 例如，給定以下數組：

$products = 
    Array
    (
        [0] => Array
            (
                [price] => 100
                [product] => cloths
                [qty] => 3
            )

        [1] => Array
            (
                [price] => 101
                [product] => cloths
                [qty] => 10
            )

        [2] => Array
            (
                [price] => 102
                [product] => cloths
                [qty] => 16
            )

        [3] => Array
            (
                [price] => 103
                [product] => cloths
                [qty] => 1
            )

        [4] => Array
            (
                [price] => 108
                [product] => cloths
                [qty] => 6
            )

        [5] => Array
            (
                [price] => 107
                [product] => cloths
                [qty] => 4
            )

        [6] => Array
            (
                [price] => 109
                [product] => cloths
                [qty] => 5
            )

        [7] => Array
            (
                [price] => 105
                [product] => cloths
                [qty] => 2
            )

        [8] => Array
            (
                [price] => 104
                [product] => cloths
                [qty] => 5
            )

        [9] => Array
            (
                [price] => 106
                [product] => cloths
                [qty] => 2
            )

        [10] => Array
            (
                [price] => 111
                [product] => cloths
                [qty] => 1
            )

    )

如何解決這個問題？

foreach ($products as $key => $product) {
    $price = $product['price'];
    //now using this price how can i get all keys which are equal to this price
}

編輯我已經嘗試過但沒有用

echo $key = array_search(100, array_column($products, 'price'));

Answer 1

請嘗試以下方法：

$keys =  array_keys(array_filter($product, function($val) {return $val['price'] == 100; })

Answer 2

我將創建一個包含價格作為鍵和產品鍵作為值的數組：

$prices = array();
foreach ($products as $key => $product) {
    $prices[$product['price']][] = $key;
}

現在， $prices[105]包含價格= 105的所有產品密鑰的數組（在特定示例中，只有一個： 7 ）：

var_dump($prices[105]);
# array(1) {
#   [0]=>
#   int(7)
# }