php - 如何遍历已转换为关联数组的json对象获取prop值

Question

我正在使用 PHP（我是菜鸟）从本地服务器检索文件。这是一个 json 文件。然后我将其转换为关联数组。但是，我在遍历属性和数组以定位我需要的值时遇到问题。

下面是数组的每个元素的样子，我试图针对每个国家的 iso2 和 name 属性/值。

array (
  'type' => 'FeatureCollection',
  'features' => 
  array (
    0 => 
    array (
      'type' => 'Feature',
      'properties' => 
      array (
        **'name' => 'Bahamas',
        'iso_a2' => 'BS',**
        'iso_a3' => 'BHS',
        'iso_n3' => '044',
      ),
      'geometry' => 
      array (
        'type' => 'MultiPolygon',
        'coordinates' => 
        array (
          0 => 
          array (
            0 => 
            array (
              0 => 
              array (
                0 => -77.53466,
                1 => 23.75975,
              ),
              1 => 
              array (
                0 => -77.78,
                1 => 23.71,
              ),
              2 => 
              array (
                0 => -78.03405,
                1 => 24.28615,
              ),
              3 => 
              array (
                0 => -78.40848,
                1 => 24.57564,
              ),
              4 => 
              array (
                0 => -78.19087,
                1 => 25.2103,
              ),
              5 => 
              array (
                0 => -77.89,
                1 => 25.17,
              ),
              6 => 
              array (
                0 => -77.54,
                1 => 24.34,
              ),
              7 => 
              array (
                0 => -77.53466,
                1 => 23.75975,
              ),
            ),
          ),
          1 => 
          array (
            0 => 
            array (
              0 => 
              array (
                0 => -77.82,
                1 => 26.58,
              ),
              1 => 
              array (
                0 => -78.91,
                1 => 26.42,
              ),
              2 => 
              array (
                0 => -78.98,
                1 => 26.79,
              ),
              3 => 
              array (
                0 => -78.51,
                1 => 26.87,
              ),
              4 => 
              array (
                0 => -77.85,
                1 => 26.84,
              ),
              5 => 
              array (
                0 => -77.82,
                1 => 26.58,
              ),
            ),
          ),
          2 => 
          array (
            0 => 
            array (
              0 => 
              array (
                0 => -77,
                1 => 26.59,
              ),
              1 => 
              array (
                0 => -77.17255,
                1 => 25.87918,
              ),
              2 => 
              array (
                0 => -77.35641,
                1 => 26.00735,
              ),
              3 => 
              array (
                0 => -77.34,
                1 => 26.53,
              ),
              4 => 
              array (
                0 => -77.78802,
                1 => 26.92516,
              ),
              5 => 
              array (
                0 => -77.79,
                1 => 27.04,
              ),
              6 => 
              array (
                0 => -77,
                1 => 26.59,
              ),
            ),
          ),
        ),
      ),
    ),

这是我尝试访问数组的方式，但无济于事

forEach($assArr["features"] as $element){
    if ($element[0]["properties"]["iso_a2"] == "BS"){
        echo_r($element[0]);
    }
}

页面输出的 内容“未定义的偏移量：0”

标签： phpassociative-array

Answer 1

$element将引用内部的值。

forEach($assArr["features"] as $element){
    if ($element["properties"]["iso_a2"] == "BS"){
        echo_r($element);
    }
}

如果需要 0，可以执行以下操作

forEach($assArr["features"] as $key => $element){
    if ($element["properties"]["iso_a2"] == "BS"){
        echo_r($key); // will be 0
        echo_r($element);
    }
}