Question

给出如下数组：

$z = [
 "cat lovers" => [
     "name" => "cat lovers",
     "impressions" => 2038,
     "ctr" => 0.032875368007851,
     "actions" => [
       [
         "action_type" => "attention_event",
         "value" => "232",
       ],
       [
         "action_type" => "landing_page_view",
         "value" => "18",
       ],
     ],
 "shorty kodi" => [
     "name" => "shorty kodi",
     "impressions" => 534,
     "ctr" => 0.041198501872659,
     "actions" => [
       [
         "action_type" => "attention_event",
         "value" => "56",
       ],
       [
         "action_type" => "landing_page_view",
         "value" => "7",
       ]
     ]
]

以下代码运行时没有错误：

foreach($z as $i) {
    print_r(array_column($i["actions"], "action_type"));
}

但是如果我们将print_r函数删除为：

foreach($z as $i) {
   $b = array_column($i["actions"], "action_type");
}

导致错误说：

PHP error:  Undefined index: actions on line 2

知道为什么吗？

谢谢

Answer 1

工作正常，我刚检查过。将print_r($b);放在foreach内或之后。您将获得与第一个foreach相同的结果。

Answer 2

提供的数组有语法错误。

试试这个：

$z = [
 "cat lovers" => [
     "name" => "cat lovers",
     "impressions" => 2038,
     "ctr" => 0.032875368007851,
     "actions" => [
       [
         "action_type" => "attention_event",
         "value" => "232",
       ],
       [
         "action_type" => "landing_page_view",
         "value" => "18",
       ],
     ]
  ],
 "shorty kodi" => [
     "name" => "shorty kodi",
     "impressions" => 534,
     "ctr" => 0.041198501872659,
     "actions" => [
       [
         "action_type" => "attention_event",
         "value" => "56",
       ],
       [
         "action_type" => "landing_page_view",
         "value" => "7",
       ]
     ]
  ]
];

foreach($z as $i) {
   $b = array_column($i["actions"], "action_type");
}

Answer 3

我不知道出了什么问题，但我应对并粘贴了你的代码，而且工作正常。

这就是我所做的。

$z = [
"cat lovers" => [
    "name" => "cat lovers",
    "impressions" => 2038,
    "ctr" => 0.032875368007851,
    "actions" => [
        [
            "action_type" => "attention_event",
            "value" => "232",
        ],
        [
            "action_type" => "landing_page_view",
            "value" => "18",
        ],
    ],
    "shorty kodi" => [
        "name" => "shorty kodi",
        "impressions" => 534,
        "ctr" => 0.041198501872659,
        "actions" => [
            [
                "action_type" => "attention_event",
                "value" => "56",
            ],
            [
                "action_type" => "landing_page_view",
                "value" => "7",
            ]
        ]
    ]
]];
$b = "";
foreach($z as $i) {
    $b=array_column($i["actions"], "action_type");
}
print_r($b);

Answer 4

对不起，我发现原因很简单。当我测试它时，阵列实际上很长，并且在其中一个元素中，没有＆＃34;动作＆＃34;索引，所有其余的都有！

这就是为什么当循环每个时，它会在那个上失败。

感谢您的所有反馈。

PHP数组索引未定义，虽然它存在

4 个答案: