尝试循环关联数组时获取未定义的索引

Question

我试图循环一个关联数组，但得到一个未定义的索引错误。

下面是数组。

{
    "first":{
        "name":"name 1",
        "products":[
            {
                "id":2,
                "product_id":123,
                "category_id":1
            },
            {
                "id":3,
                 "product_id":"456"
            }
        ]
    }
}

我试图像

那样循环使用

foreach ($array as $category => $products) {
    echo $category;
    foreach ($products['products'] as $product) {
        echo $product->id;
    }
}

但我得到了

Undefined index: products

如何遍历产品阵列？

Answer 1

您需要将$products['products']更改为$products->products因为 $products是对象而非数组。

$test='{"first":{"name":"name 1","products":[
{"id":2,"product_id":123,"category_id":1},{"id":3,"product_id":"456"}
]}}';
echo "<pre>";
$array=json_decode($test);
foreach($array as $category => $products){
    foreach($products->products as $product){
        echo $product->id."<br/>";
    }                
}

demo.....