GrouBy Data Expression

JanelleShank

Good Afternoon, All!

I have a dataset of voting results and I can trying to create a data expression that returns the MAX value of registered voters within each district and then add the total of each MAX value to find the total number of those registered. I have written a data expression using the GoupBy function, however, it is returning a null value. I have provided examples of my data expression and data below. 

 

var fs = FeaturesetByPortalItem(Portal("https://bedfordplanning.maps.arcgis.com"), "78eb292ce436450b85dc249bd3069741", 0, ["Precinct_name", "Reg_voters"], false)

var out_dict = {

  fields: [

    {name: "Precinct_Name", type: "esriFieldTypeString"},

    {name: "Reg_voters", type: "esriFieldTypeString"}

  ],

  features: [],

  geometryType: ""

}

var maxvotes = GroupBy("out_dict", 'Precinct_Name', {name: 'Reg_voters', expression: 'Reg_Voters', statistic: "MAX"})

 

Thank you,

Janelle

kenbuja

Since your data is private, I can't test it. However, I was able to test using a public service and it worked as expected, returning two items in the table with the maximum value for each aggregationMethod

var fs =  FeatureSetByPortalItem(
    Portal("https://www.arcgis.com"),
    // portal item id
    "7b1fb95ab77f40bf8aa09c8b59045449",
    0, // layer id
    ["*"], // fields to include
    false // include or exclude geometry
  );

GroupBy(fs, 'aggregationMethod', {name: 'TOTPOP_CY', expression: 'TOTPOP_CY', statistic: "MAX"})