javascript - 如何通过选择对象中的特定属性来使用 map 功能-6ren

javascript - 如何通过选择对象中的特定属性来使用 map 功能

转载作者：行者123 更新时间：2023-11-29 20:58:53

我有一个像这样的动态对象 data。有什么方法可以像这样映射数据吗？

我需要的是用 Transformer 和 Service Point 的特定值映射所有属性的 geometry 并将它们加载到数组中。

var transformers = [
                    [-88.17602806699995, 41.78431233100008],
                    [-88.17546081099994, 41.783341919000065]
                   ]

或

var servicePoints = [
                    [-88.17599727899994, 41.78465526100007],
                    [-88.17595382899998, 41.78455803400004],
                    [-88.17582231499995, 41.78435312600004],
                    [-88.17561004899994, 41.78400533500074],
                    [-88.17557576699994, 41.78393182000008],
                    [-88.17535967199996, 41.78352876900004]
                   ]

这是数据集

var data = [{
    "displayFieldName": "",
    "fieldAliases": {
      "OBJECTID": "OBJECTID"
    },
    "fields": [{
      "name": "OBJECTID",
      "type": "esriFieldTypeOID",
      "alias": "OBJECTID"
    }],
    "features": [{
        "attributes": {
          "OBJECTID": 649
        }
      },
      {
        "attributes": {
          "OBJECTID": 665
        }
      },
      {
        "attributes": {
          "OBJECTID": 762
        }
      }
    ]
  },
  {
    "displayFieldName": "",
    "fieldAliases": {
      "display": "display",
      "OBJECTID": "OBJECTID"
    },
    "geometryType": "esriGeometryPoint",
    "spatialReference": {
      "wkid": 4326,
      "latestWkid": 4326
    },
    "fields": [{
        "name": "display",
        "type": "esriFieldTypeString",
        "alias": "display",
        "length": 50
      },
      {
        "name": "OBJECTID",
        "type": "esriFieldTypeOID",
        "alias": "OBJECTID"
      }
    ],
    "features": [{
        "attributes": {
          "display": "Transformer",
          "OBJECTID": 1537
        },
        "geometry": {
          "x": -88.17602806699995,
          "y": 41.78431233100008
        }
      },
      {
        "attributes": {
          "display": "Transformer",
          "OBJECTID": 1591
        },
        "geometry": {
          "x": -88.17546081099994,
          "y": 41.783341919000065
        }
      }
    ]
  },
  {
    "displayFieldName": "",
    "fieldAliases": {
      "display": "display",
      "OBJECTID": "OBJECTID"
    },
    "geometryType": "esriGeometryPoint",
    "spatialReference": {
      "wkid": 4326,
      "latestWkid": 4326
    },
    "fields": [{
        "name": "display",
        "type": "esriFieldTypeString",
        "alias": "display",
        "length": 50
      },
      {
        "name": "OBJECTID",
        "type": "esriFieldTypeOID",
        "alias": "OBJECTID"
      }
    ],
    "features": [{
        "attributes": {
          "display": "Service Point",
          "OBJECTID": 13597
        },
        "geometry": {
          "x": -88.17599727899994,
          "y": 41.78465526100007
        }
      },
      {
        "attributes": {
          "display": "Service Point",
          "OBJECTID": 13598
        },
        "geometry": {
          "x": -88.17595382899998,
          "y": 41.78455803400004
        }
      },
      {
        "attributes": {
          "display": "Service Point",
          "OBJECTID": 13599
        },
        "geometry": {
          "x": -88.17582231499995,
          "y": 41.78435312600004
        }
      },
      {
        "attributes": {
          "display": "Service Point",
          "OBJECTID": 13600
        },
        "geometry": {
          "x": -88.17561004899994,
          "y": 41.784005335000074
        }
      },
      {
        "attributes": {
          "display": "Service Point",
          "OBJECTID": 13601
        },
        "geometry": {
          "x": -88.17557576699994,
          "y": 41.78393182000008
        }
      },
      {
        "attributes": {
          "display": "Service Point",
          "OBJECTID": 13602
        },
        "geometry": {
          "x": -88.17535967199996,
          "y": 41.78352876900004
        }
      },
      {
        "attributes": {
          "display": "Service Point",
          "OBJECTID": 13603
        },
        "geometry": {
          "x": -88.17534426199995,
          "y": 41.78340020400003
        }
      },
      {
        "attributes": {
          "display": "Service Point",
          "OBJECTID": 13649
        },
        "geometry": {
          "x": -88.17450698899995,
          "y": 41.78350136200004
        }
      },
      {
        "attributes": {
          "display": "Service Point",
          "OBJECTID": 13650
        },
        "geometry": {
          "x": -88.17435162999999,
          "y": 41.783597986000075
        }
      }
    ]
  }
];

我已经试过了:

var transformers = data.map((obj) => obj.features.map(({attributes})=>attributes.display || "NONE"));

但这只会在没有几何形状的不同数组中返回它们!

最佳答案

您可以遍历 data 中所有对象的所有特征，并在进行时累积结果:

function get(data, attributeType) {
    return data.reduce(function(acc, obj) {                               // for each object obj in the array data
        obj.features.forEach(function(feature) {                          // for each feature feature in the array features of obj
            if(feature.attributes                                         // if this feature has an attributes property
               && typeof feature.attributes === "object"                  // and that attributes property is an object
               && feature.attributes.display === attributeType) {         // and the display property of this feature's attributes is the same as attributeType
                acc.push([feature.geometry.x, feature.geometry.y]);       // then push the coordinates of its geometry coordinates to acc
            }
        });
        return acc;
    }, []);
}

然后要获取转换，您可以这样调用 get:

var transformers = get(data, "Transformer");

为了获得服务点，您可以这样调用它:

var servicePoints = get(data, "Service Point");

示例:

function get(data, attributeType) {
    return data.reduce(function(acc, obj) {                               // for each object obj in the array data
        obj.features.forEach(function(feature) {                          // for each feature feature in the array features of obj
            if(feature.attributes                                         // if this feature has an attributes property
               && typeof feature.attributes === "object"                  // and that attributes property is an object
               && feature.attributes.display === attributeType) {         // and the display property of this feature's attributes is the same as attributeType
                acc.push([feature.geometry.x, feature.geometry.y]);       // then push the coordinates of its geometry coordinates to acc
            }
        });
        return acc;
    }, []);
}

var data = [{"displayFieldName":"","fieldAliases":{"OBJECTID":"OBJECTID"},"fields":[{"name":"OBJECTID","type":"esriFieldTypeOID","alias":"OBJECTID"}],"features":[{"attributes":{"OBJECTID":649}},{"attributes":{"OBJECTID":665}},{"attributes":{"OBJECTID":762}}]},{"displayFieldName":"","fieldAliases":{"display":"display","OBJECTID":"OBJECTID"},"geometryType":"esriGeometryPoint","spatialReference":{"wkid":4326,"latestWkid":4326},"fields":[{"name":"display","type":"esriFieldTypeString","alias":"display","length":50},{"name":"OBJECTID","type":"esriFieldTypeOID","alias":"OBJECTID"}],"features":[{"attributes":{"display":"Transformer","OBJECTID":1537},"geometry":{"x":-88.17602806699995,"y":41.78431233100008}},{"attributes":{"display":"Transformer","OBJECTID":1591},"geometry":{"x":-88.17546081099994,"y":41.783341919000065}}]},{"displayFieldName":"","fieldAliases":{"display":"display","OBJECTID":"OBJECTID"},"geometryType":"esriGeometryPoint","spatialReference":{"wkid":4326,"latestWkid":4326},"fields":[{"name":"display","type":"esriFieldTypeString","alias":"display","length":50},{"name":"OBJECTID","type":"esriFieldTypeOID","alias":"OBJECTID"}],"features":[{"attributes":{"display":"Service Point","OBJECTID":13597},"geometry":{"x":-88.17599727899994,"y":41.78465526100007}},{"attributes":{"display":"Service Point","OBJECTID":13598},"geometry":{"x":-88.17595382899998,"y":41.78455803400004}},{"attributes":{"display":"Service Point","OBJECTID":13599},"geometry":{"x":-88.17582231499995,"y":41.78435312600004}},{"attributes":{"display":"Service Point","OBJECTID":13600},"geometry":{"x":-88.17561004899994,"y":41.784005335000074}},{"attributes":{"display":"Service Point","OBJECTID":13601},"geometry":{"x":-88.17557576699994,"y":41.78393182000008}},{"attributes":{"display":"Service Point","OBJECTID":13602},"geometry":{"x":-88.17535967199996,"y":41.78352876900004}},{"attributes":{"display":"Service Point","OBJECTID":13603},"geometry":{"x":-88.17534426199995,"y":41.78340020400003}},{"attributes":{"display":"Service Point","OBJECTID":13649},"geometry":{"x":-88.17450698899995,"y":41.78350136200004}},{"attributes":{"display":"Service Point","OBJECTID":13650},"geometry":{"x":-88.17435162999999,"y":41.783597986000075}}]}];


var transformers = get(data, "Transformer");
var servicePoints = get(data, "Service Point");

console.log("Transformers:", transformers);
console.log("servicePoints:", servicePoints);

关于javascript - 如何通过选择对象中的特定属性来使用 map 功能，我们在Stack Overflow上找到一个类似的问题： https://stackoverflow.com/questions/47777548/

文章推荐： mysql - 如何根据列的子字符串更改列的值？

文章推荐： mysql - Rails 4.0 将数组和字符串保存到单列

java - 对象 a = 对象 b；对象 a 会发生什么？
我的一位教授给了我们一些考试练习题，其中一个问题类似于下面(伪代码): a.setColor(blue); b.setColor(red); a = b; b.setColor(purple); b
JavaScript 测试(对象 && 对象 !== "null"&& 对象 !== "undefined")
我似乎经常使用这个测试 if( object && object !== "null" && object !== "undefined" ){ doSomething(); } 在对象上，我
C#对象/对象
C# Object/object 是值类型还是引用类型？我检查过它们可以保留引用，但是这个引用不能用于更改对象。 using System; class MyClass { public s
javascript - 通过ajax发送json - 对象 - 对象
我在通过 AJAX 发送 json 时遇到问题。 var data = [{"name": "Will", "surname": "Smith", "age": "40"},{"name": "Wil
javascript - 如何获取值[对象][对象]
当我尝试访问我的 View 中的对象 {{result}} 时(我从 Express js 服务器发送该对象)，它只显示 [object][object]有谁知道如何获取 JSON 格式的值吗？这是
java - 对象...对象[] 和格式
我有不同类型的数据(可能是字符串、整数......)。这是一个简单的例子: public static void main(String[] args) { before("one"); }
javascript - 如何修复[对象，对象]
嗨，我是 json 和 javascript 的新手。我在这个网站找到了使用json数据作为表格的方法。我很好奇为什么当我尝试使用 json 数据作为表时，我得到 [Object,Object]
JavaScript [对象][对象] 调试
已关闭。此问题需要 debugging details 。目前不接受答案。编辑问题以包含 desired behavior, a specific problem or error, and the
java - 对象==空或空==对象？
我听别人说 null == object 比 object == null check 例如: void m1(Object obj ) { if(null == obj) // Is thi
VBS教程：对象-Match 对象
Match 对象提供了对正则表达式匹配的只读属性的访问。说明 Match 对象只能通过 RegExp 对象的 Execute 方法来创建，该方法实际上返回了 Match 对象的集合。所有的
VBS教程：对象-Class 对象
Class 对象使用 Class 语句创建的对象。提供了对类的各种事件的访问。说明不允许显式地将一个变量声明为 Class 类型。在 VBScript 的上下文中，“类对象”一词指的是用
VBS教程：对象-Folder 对象
Folder 对象提供对文件夹所有属性的访问。说明以下代码举例说明如何获得 Folder 对象并查看它的属性： Function ShowDateCreated(f
VBS教程：对象-File 对象
File 对象提供对文件的所有属性的访问。说明以下代码举例说明如何获得一个 File 对象并查看它的属性： Function ShowDateCreated(fil
VBS教程：对象-Drive 对象
Drive 对象提供对磁盘驱动器或网络共享的属性的访问。说明以下代码举例说明如何使用 Drive 对象访问驱动器的属性： Function ShowFreeSpac
VBS教程：对象-FileSystemObject 对象
FileSystemObject 对象提供对计算机文件系统的访问。说明以下代码举例说明如何使用 FileSystemObject 对象返回一个 TextStream 对象，此对象可以被读
对象
我是 javascript OOP 的新手，我认为这是一个相对基本的问题，但我无法通过搜索网络找到任何帮助。我是否遗漏了什么，或者我只是以错误的方式解决了这个问题？这是我的示例代码: functio
对象
我可以很容易地创造出很多不同的对象。例如像这样: var myObject = { myFunction: function () { return ""; } };
对象
function Person(fname, lname) { this.fname = fname, this.lname = lname, this.getName = function()
javascript - JSON 返回(对象，对象)
任何人都可以向我解释为什么下面的代码给出 (object, Object) 吗？ (console.log(dope) 给出了它应该的内容，但在 JSON.stringify 和 JSON.parse
javascript - 返回 [对象，对象] 的工具提示
我正在尝试完成散点图 exercise来自免费代码营。然而，我现在只自己学习了 d3 几个小时，在遵循 lynda.com 的教程后，我一直在尝试确定如何在工具提示中显示特定数据。 This code

行者123

个人简介

我是一名优秀的程序员,十分优秀！

作者热门文章

滴滴打车优惠券免费领取

全站热门文章

首页

博学

6Ren·AI

商城

javascript - 如何通过选择对象中的特定属性来使用 map 功能