javascript - 访问未命名对象的属性(对象内)

标签 javascript jquery

我正在使用 Javascript/JQuery 来使用 Google Web 服务，并且可以毫无问题地检索 JSON 结果，并将它们存储在 var(名为 searchResults)中。在此示例中，我只是将对象中要显示的所有信息(address_components 的每个子对象中的 long_name 以及 lat 和 lng 值)添加到字符串 var (displayTxt)。

但是，结果中有许多未命名的对象，我找不到一种简单的方法来定位它们。我想使用标准的 object.property 语法，尽管如果对象没有命名(并且有多个对象)，这是不可能的。我已经使用嵌入式 $.each 循环来循环遍历每个连续的对象，并且这个解决方案确实有效，但我认为它不是很整洁。所以我的问题是:是否有更好的方法来达到相同的结果？

$( "#displayBtn" ).click(function()
 {
    var displayTxt = "";
    if (searchResults.results)
        {

            $.each(searchResults.results, function (k,v)
                   {
                    displayTxt +=( "Result ID: " + k + "<br>");
                    $.each(v,function(a,b)
                           {
                            if(a=="address_components")
                                { 
                                $.each(b,function(c,d)
                                       {
                                        displayTxt += (d.long_name + "<br>")
                                        })
                                }
                            })
                    displayTxt+= "lat:" + v.geometry.location.lat +"<br>";
                    displayTxt+= "lng:" + v.geometry.location.lng +"<br><br>";
                   }
                  )

        };
     $('#resultsDisplay').html(displayTxt); 
});

这是 searchResults 对象:

{
"results" : [
  {
     "address_components" : [
        {
           "long_name" : "Reading",
           "short_name" : "Reading",
           "types" : [ "locality", "political" ]
        },
        {
           "long_name" : "Exeter",
           "short_name" : "Exeter",
           "types" : [ "administrative_area_level_3", "political" ]
        },
        {
           "long_name" : "Berks County",
           "short_name" : "Berks County",
           "types" : [ "administrative_area_level_2", "political" ]
        },
        {
           "long_name" : "Pennsylvania",
           "short_name" : "PA",
           "types" : [ "administrative_area_level_1", "political" ]
        },
        {
           "long_name" : "United States",
           "short_name" : "US",
           "types" : [ "country", "political" ]
        }
     ],
     "formatted_address" : "Reading, PA, USA",
     "geometry" : {
        "bounds" : {
           "northeast" : {
              "lat" : 40.371134,
              "lng" : -75.890512
           },
           "southwest" : {
              "lat" : 40.296401,
              "lng" : -75.9598731
           }
        },
        "location" : {
           "lat" : 40.3356483,
           "lng" : -75.9268747
        },
        "location_type" : "APPROXIMATE",
        "viewport" : {
           "northeast" : {
              "lat" : 40.371134,
              "lng" : -75.890512
           },
           "southwest" : {
              "lat" : 40.296401,
              "lng" : -75.9598731
           }
        }
     },
     "types" : [ "locality", "political" ]
  },
  {
     "address_components" : [
        {
           "long_name" : "Reading",
           "short_name" : "Reading",
           "types" : [ "locality", "political" ]
        },
        {
           "long_name" : "Reading",
           "short_name" : "Reading",
           "types" : [ "postal_town" ]
        },
        {
           "long_name" : "Reading",
           "short_name" : "Reading",
           "types" : [ "administrative_area_level_2", "political" ]
        },
        {
           "long_name" : "England",
           "short_name" : "England",
           "types" : [ "administrative_area_level_1", "political" ]
        },
        {
           "long_name" : "United Kingdom",
           "short_name" : "GB",
           "types" : [ "country", "political" ]
        }
     ],
     "formatted_address" : "Reading, Reading, Reading, UK",
     "geometry" : {
        "bounds" : {
           "northeast" : {
              "lat" : 51.4931339,
              "lng" : -0.9284944000000001
           },
           "southwest" : {
              "lat" : 51.4097795,
              "lng" : -1.0636011
           }
        },
        "location" : {
           "lat" : 51.4542645,
           "lng" : -0.9781303
        },
        "location_type" : "APPROXIMATE",
        "viewport" : {
           "northeast" : {
              "lat" : 51.4931339,
              "lng" : -0.9284944000000001
           },
           "southwest" : {
              "lat" : 51.4097795,
              "lng" : -1.0636011
           }
        }
     },
     "types" : [ "locality", "political" ]
  },
  {
     "address_components" : [
        {
           "long_name" : "Reading",
           "short_name" : "Reading",
           "types" : [ "locality", "political" ]
        },
        {
           "long_name" : "Middlesex County",
           "short_name" : "Middlesex County",
           "types" : [ "administrative_area_level_2", "political" ]
        },
        {
           "long_name" : "Massachusetts",
           "short_name" : "MA",
           "types" : [ "administrative_area_level_1", "political" ]
        },
        {
           "long_name" : "United States",
           "short_name" : "US",
           "types" : [ "country", "political" ]
        }
     ],
     "formatted_address" : "Reading, MA, USA",
     "geometry" : {
        "bounds" : {
           "northeast" : {
              "lat" : 42.566432,
              "lng" : -71.07103499999999
           },
           "southwest" : {
              "lat" : 42.5006449,
              "lng" : -71.1361789
           }
        },
        "location" : {
           "lat" : 42.5256563,
           "lng" : -71.0952891
        },
        "location_type" : "APPROXIMATE",
        "viewport" : {
           "northeast" : {
              "lat" : 42.566432,
              "lng" : -71.07103499999999
           },
           "southwest" : {
              "lat" : 42.5006449,
              "lng" : -71.1361789
           }
        }
     },
     "types" : [ "locality", "political" ]
  },
  {
     "address_components" : [
        {
           "long_name" : "Reading",
           "short_name" : "Reading",
           "types" : [ "locality", "political" ]
        },
        {
           "long_name" : "Hamilton County",
           "short_name" : "Hamilton County",
           "types" : [ "administrative_area_level_2", "political" ]
        },
        {
           "long_name" : "Ohio",
           "short_name" : "OH",
           "types" : [ "administrative_area_level_1", "political" ]
        },
        {
           "long_name" : "United States",
           "short_name" : "US",
           "types" : [ "country", "political" ]
        }
     ],
     "formatted_address" : "Reading, OH, USA",
     "geometry" : {
        "bounds" : {
           "northeast" : {
              "lat" : 39.240921,
              "lng" : -84.407549
           },
           "southwest" : {
              "lat" : 39.2038819,
              "lng" : -84.454735
           }
        },
        "location" : {
           "lat" : 39.2236694,
           "lng" : -84.44216410000001
        },
        "location_type" : "APPROXIMATE",
        "viewport" : {
           "northeast" : {
              "lat" : 39.240921,
              "lng" : -84.407549
           },
           "southwest" : {
              "lat" : 39.2038819,
              "lng" : -84.454735
           }
        }
     },
     "types" : [ "locality", "political" ]
  },
  {
     "address_components" : [
        {
           "long_name" : "Reading",
           "short_name" : "Reading",
           "types" : [ "locality", "political" ]
        },
        {
           "long_name" : "Windsor County",
           "short_name" : "Windsor County",
           "types" : [ "administrative_area_level_2", "political" ]
        },
        {
           "long_name" : "Vermont",
           "short_name" : "VT",
           "types" : [ "administrative_area_level_1", "political" ]
        },
        {
           "long_name" : "United States",
           "short_name" : "US",
           "types" : [ "country", "political" ]
        }
     ],
     "formatted_address" : "Reading, VT, USA",
     "geometry" : {
        "bounds" : {
           "northeast" : {
              "lat" : 43.561169,
              "lng" : -72.53007579999999
           },
           "southwest" : {
              "lat" : 43.4440849,
              "lng" : -72.66064299999999
           }
        },
        "location" : {
           "lat" : 43.494167,
           "lng" : -72.59638900000002
        },
        "location_type" : "APPROXIMATE",
        "viewport" : {
           "northeast" : {
              "lat" : 43.561169,
              "lng" : -72.53007579999999
           },
           "southwest" : {
              "lat" : 43.4440849,
              "lng" : -72.66064299999999
           }
        }
     },
     "types" : [ "locality", "political" ]
  },
  {
     "address_components" : [
        {
           "long_name" : "Reading",
           "short_name" : "Reading",
           "types" : [ "locality", "political" ]
        },
        {
           "long_name" : "Summit Lake",
           "short_name" : "Summit Lake",
           "types" : [ "administrative_area_level_3", "political" ]
        },
        {
           "long_name" : "Nobles County",
           "short_name" : "Nobles County",
           "types" : [ "administrative_area_level_2", "political" ]
        },
        {
           "long_name" : "Minnesota",
           "short_name" : "MN",
           "types" : [ "administrative_area_level_1", "political" ]
        },
        {
           "long_name" : "United States",
           "short_name" : "US",
           "types" : [ "country", "political" ]
        },
        {
           "long_name" : "56165",
           "short_name" : "56165",
           "types" : [ "postal_code" ]
        }
     ],
     "formatted_address" : "Reading, MN 56165, USA",
     "geometry" : {
        "location" : {
           "lat" : 43.7035752,
           "lng" : -95.7130676
        },
        "location_type" : "APPROXIMATE",
        "viewport" : {
           "northeast" : {
              "lat" : 43.70492418029149,
              "lng" : -95.71171861970849
           },
           "southwest" : {
              "lat" : 43.70222621970849,
              "lng" : -95.71441658029151
           }
        }
     },
     "types" : [ "locality", "political" ]
  }
],
"status" : "OK"
}

最佳答案

看起来好像你有一个对象数组，这些对象没有名称(它们没有分配给变量，只是数组的一部分)。不过，您确实有一些不同的选项来迭代数组。

经典的迭代器是使用长度的for循环，如:

var data = [{value: 1}, {value: 2}, {value: 3}, {value: 4}, {value: 5}];

for (var i = 0; i < data.length; ++i) {
  console.log(data[i].value);
}

这将记录遇到的每个项目，并使用数组索引来访问它们。项目是什么并不重要，您只需更改数组内的逻辑即可。与 $.each 一样，您可以嵌套这些循环(只需确保使用不同的变量)。

如果您有权使用一些新的 JS 功能，则已将 forEach 方法添加到数组中，它允许您执行以下操作:

var data = [{value: 1}, {value: 2}, {value: 3}, {value: 4}, {value: 5}];

data.forEach(function(it) {
  console.log(it.value);
});

这更像是 $.each，但内置于数组中，并且在迭代 DOM 元素等时不具有相同的语义。同样，您可以嵌套它们，但无需担心计数器。这是推荐的方式(如果可用)。

无论哪种方式，一旦你拥有了该项目(通过从数组访问它)，你就拥有了它的“名称”(它已被分配给一个变量)，并且你可以使用正常的对象访问语法来获取其中的属性对象。

如果您想将数据转换为新数组或将元素合并为单个返回值，您可以查看类似 map 的方法。或reduce ，现在可在数组上使用(之前可在 Underscore 和 lodash 等库中使用)。

关于javascript - 访问未命名对象的属性(对象内)，我们在Stack Overflow上找到一个类似的问题： https://stackoverflow.com/questions/28155297/

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