从动态对象映射并生成数组

Question

我有一个像这样的动态物体

[  
   {  
      "displayFieldName":"",
      "fieldAliases":{  
         "OBJECTID":"OBJECTID"
      },
      "geometryType":"esriGeometryPoint",
      "spatialReference":{  
         "wkid":102100,
         "latestWkid":3857
      },
      "fields":[  
         {  
            "name":"OBJECTID",
            "type":"esriFieldTypeOID",
            "alias":"OBJECTID"
         }
      ],
      "features":[  
         {  
            "attributes":{  
               "OBJECTID":5270
            },
            "geometry":{  
               "x":-9814184.757,
               "y":5130582.574600004
            }
         },
         {  
            "attributes":{  
               "OBJECTID":5271
            },
            "geometry":{  
               "x":-9814152.5879,
               "y":
            }
         },
         {  
            "attributes":{  
               "OBJECTID":5272
            },
            "geometry":{  
               "x":-9814147.7353,
               "y":5130632.882600002
            }
         },
         ...
         ]
     }
]

如何从几何节点中获取x和Y并将它们加载到新数组中，就像

var points =  ['-9814184.757,5130582.574600004',
               '-9814152.5879, 5130624.636799999', 
                '-9814147.7353,5130632.882600002',
              ...,
              ]

我已经尝试过了

map = data.map(a => a.geometry.x, a => a.geometry.x);
console.log(map);`

但这只是将x值添加到数组中。

Answer 1

正如您已正确指出问题一样，可以将Array.prototype.map用于此任务。 您所要做的就是使用map作为对象的features数组，如下所示：

/* Use 'map' to concatenate together each geometry value-pair into a string. */
var points = features.map((obj)=>obj.geometry.x + ", " + obj.geometry.y);

作为替代方案，您可以将每个对放在子数组中，并对上面的代码稍作调整：

/* Use 'map' to put each geometry value-pair into an array. */
var points = features.map((obj)=>[obj.geometry.x, obj.geometry.y]);

请查看下面的代码片段，以查看完整的代码。

片段：

 /* The 'features' array of your object. */ var features = [ { "attributes":{ "OBJECTID":5270 }, "geometry":{ "x":-9814184.757, "y":5130582.574600004 } }, { "attributes":{ "OBJECTID":5271 }, "geometry":{ "x":-9814152.5879, "y": 5130624.636799999 } }, { "attributes":{ "OBJECTID":5272 }, "geometry":{ "x":-9814147.7353, "y":5130632.882600002 } } ] /* Use 'map' to concatenate together each geometry value-pair into a string. */ var points1 = features.map((obj)=>obj.geometry.x + ", " + obj.geometry.y); /* Use 'map' to put each geometry value-pair into an array. */ var points2 = features.map((obj)=>[obj.geometry.x, obj.geometry.y]); /* Log the results. */ console.log("as strings: ", points1); console.log("as sub-arrays: ", points2);