Question

在for循环中，我试图计算从JSON提要解码的嵌套数组中的飞行次数。不幸的是，当有更多航班可用时，它仅显示2个航班。我在做什么错了？

来自端点的Json feed示例

{
  "response": [
    {
      "flight": {
        "number": "6204",
        "iata_number": "HV6204",
        "icao_number": "TRA6204"
      }
    },
    {
      "flight": {
        "number": "7012",
        "iata_number": "TB7012",
        "icao_number": "JAF7012"
      }
    },
    {
      "flight": {
        "number": "6652",
        "iata_number": "HV6652",
        "icao_number": "TRA6652"
      }
    },
    {
      "flight": {
        "number": "1925",
        "iata_number": "W61925",
        "icao_number": "WZZ1925"
      }
    },
    {
      "flight": {
        "number": "5075",
        "iata_number": "W65075",
        "icao_number": "WZZ5075"
      }
    },
    {
      "flight": {
        "number": "4289",
        "iata_number": "W64289",
        "icao_number": "WZZ4289"
      }
    },
    {
      "flight": {
        "number": "7861",
        "iata_number": "W67861",
        "icao_number": "WZZ7861"
      }
    },
    {
      "flight": {
        "number": "3066",
        "iata_number": "FR3066",
        "icao_number": "RYR3066"
      }
    }
  ]
} .

PHP代码示例

<?php    
$url = 'https://api.endpoint'; // path to JSON file
$data = file_get_contents($url); 
$flights = json_decode($data, true); 

for($i=0; $i<=count($flights['response'][0]['flight']['iata_number']); $i++) {
    echo "Flightnumber" . $flights['response'][$i]['flight']["iata_number"] . '<br/>';
}
?>

非常感谢您的帮助

Answer 1

这里真正应该使用的是foreach。使用foreach，您不必关心数组的count()：

$url = 'https://api.endpoint'; // path to JSON file
$data = file_get_contents($url); 
$flights = json_decode($data, true); 

foreach ($flights['response'] as $item) {
    echo $item['flight']['iata_number'] . '<br />';
}

简单的演示是here。

如果您仍然想使用for循环，它应该看起来像：

for ($i = 0; $i < count($flights['response']); $i++) {
    echo $flights['response'][$i]['flight']['iata_number'] . '<br />';
}

Answer 2

for($i=0; $i<=count($flights['response'][0]['flight']['iata_number']); $i++) {
    echo "Flightnumber" . $flights['response'][$i]['flight']["iata_number"] . '<br/>';
}

count($flights['response'][0]['flight']['iata_number'])总是等于1，因此您只会像预期的那样循环两次（两次飞行）。我的猜测是应该是count($flights['response'])或类似的东西。

Answer 3

您可以使用array_walk_recursive

 array_walk_recursive($jarr, function($v, $k) use (&$flights){
  if($k == 'iata_number') $flights[] = $v;
});

实时示例：-https://3v4l.org/5Rp9K

计算嵌套数组中的元素数量

3 个答案: