jsonオブジェクトの配列のforeach（）エラーの引数が無効です

Question

jsonオブジェクトの配列をhtmlリストにデコードしています。私はいくつかのデモを試してみましたが、このjson配列を処理すると、次のようなエラーが発生します。foreach（）に無効な引数が渡されました。私は何が足りないのですか？

<?php 
$json_string = '{"error":false,"data":[{"jb_product_category_id":"1","jb_product_category_name":"Mother","jb_product_category_prefix":"jbpm","jb_product_category_delete_status":"0","jb_product_category_created_on":"1501500876531","jb_product_category_updated_on":"1501500876531","subCategory1":[{"jb_product_subcategory1_1_id":"1","jb_product_subcategory1_2_category_id":"1","jb_product_subcategory1_3_name":"Cloths","jb_product_subcategory1_4_delete_status":"0","jb_product_subcategory1_5_created_on":"1501563015164","jb_product_subcategory1_6_updated_on":"1501563015164","subCategory2":[{"jb_product_subcategory2_1_id":"1","jb_product_subcategory2_2_category_id":"1","jb_product_subcategory2_3_subcategory1_id":"1","jb_product_subcategory2_4_name":"Pregnancy wear","jb_product_subcategory2_5_delete_status":"0","jb_product_subcategory2_6_created_on":"1501574226464","jb_product_subcategory2_7_updated_on":"1501574226464"}]}]},{"jb_product_category_id":"2","jb_product_category_name":"Child Wear","jb_product_category_prefix":"jbpc","jb_product_category_delete_status":"0","jb_product_category_created_on":"1502429483534","jb_product_category_updated_on":"1502429483534","subCategory1":[{"jb_product_subcategory1_1_id":"2","jb_product_subcategory1_2_category_id":"2","jb_product_subcategory1_3_name":"Girls","jb_product_subcategory1_4_delete_status":"0","jb_product_subcategory1_5_created_on":"1502429606169","jb_product_subcategory1_6_updated_on":"1502429606169","subCategory2":[{"jb_product_subcategory2_1_id":"2","jb_product_subcategory2_2_category_id":"2","jb_product_subcategory2_3_subcategory1_id":"2","jb_product_subcategory2_4_name":"Western","jb_product_subcategory2_5_delete_status":"0","jb_product_subcategory2_6_created_on":"1502429794573","jb_product_subcategory2_7_updated_on":"1502429794573"}]},{"jb_product_subcategory1_1_id":"3","jb_product_subcategory1_2_category_id":"2","jb_product_subcategory1_3_name":"Boys","jb_product_subcategory1_4_delete_status":"0","jb_product_subcategory1_5_created_on":"1505105190176","jb_product_subcategory1_6_updated_on":"1505105190176","subCategory2":[]}]}]}'; 

    $array = json_decode($json_string, true); 
    function build_list($array) { 
    $list = '<ul>'; 
    foreach($array as $key => $value) { 
    foreach($value as $key => $index) { 
    if(is_array($index)) { 
     $list .= build_list($index); 
     } else { 
     $list .= "<li>$index</li>"; 
     } 
    } 
    } 

     $list .= '</ul>'; 
    return $list; 
     } 

echo build_list($array); 
    ?> 

Answer 1

単純に一つだけのforeachを使用して、ネストされた一つが役に立たないようだ：

foreach($array as $key => $index) { 
    if(is_array($index)) { 
    /* ... */ 

Answer 2

$valueが有効な配列であるかどうかだけをチェックするための条件を追加します。この方法では、配列でなく警告が消える場合は$valueを処理しません。

if (!is_array($value)) { 
     continue; 
    } 

ループ$array前foreachの内側に、この条件を使用してください。

foreach($array as $key => $value) { 
    if (!is_array($value)) { 
     continue; 
    } 

    foreach($value as $k => $index) { 
    if(is_array($index)) { 
     $list .= build_list($index); 
     } else { 
     $list .= "<li>$index</li>"; 
     } 
    } 
} 

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