Object with Key:Value where every Value is an Array of Objects - cannot iterate

Question

I am downloading data via d3.json when create an object with each record that holds downloaded data. Each object will be stored in an array. I lost the ability to iterate over the array.

I have tried using multi-dimensional array, and still cannot iterate over the created object.

var datamodel = {
    "mkt":[],
    "confidence":[],
    "homes":[],
    "combined":[]
}

var tObject={};

// console.log(datamodel)
const url1 = "https://www.quandl.com/api/v3/datasets/YALE/SPCOMP.json?start_date='2015-01-01'&end_date='2018-09-30'&api_key=4QuxetVDNP8R3sYg9CED";

// Fetch the JSON data and console log it
d3.json(url1).then(function(data) {
    data.dataset.data.forEach(element => {
        tObject['date']=element[0];
        tObject['spx'] = element[1];
        tObject['rate']=element[5];
        datamodel['mkt'].push(tObject); //creating an array of objects
        tObject={};
    });
});

I repeat the code above for other datasets to fill "confidence, homes" I need to iterate after downloading over the datamodel, and update the "combined" so that I can have more stats, like change per date, ratios. For instance: going to debug console in any browser, I can access the datamodel variable via datamodel.mkt

The debug console allows me to iterate over the objects, not sure why code ran in JS file does not allow me to iterate not get length of the array. I am so lost.

score -1 · Answer 1 · answered Aug 24 '19 at 05:46

I hit the API in browser and copied the data in my js file. I call this function in HTML onload. Half of this function does what your code did to fill data in datamodel.mkt

Then it loops over the data present in datamodel.mkt and copies the elements in datamodel.combined

Please note that the commented forEach loop also works. You can uncomment the console.log to view the datamodel object in console

Hope this helps.

function setData(){

 var data = {"dataset":{"id":539984,"dataset_code":"SPCOMP","database_code":"YALE","name":"S\u0026P Composite","description":"This data set consists of monthly stock price, dividends, and earnings data and the consumer price index (to allow conversion to real values), all starting January 1871. Further info at http://www.econ.yale.edu/~shiller/data.htm.","refreshed_at":"2019-08-24T02:51:26.805Z","newest_available_date":"2019-08-31","oldest_available_date":"1871-01-31","column_names":["Year","S\u0026P Composite","Dividend","Earnings","CPI","Long Interest Rate","Real Price","Real Dividend","Real Earnings","Cyclically Adjusted PE Ratio"],"frequency":"monthly","type":"Time Series","premium":false,"limit":null,"transform":null,"column_index":null,"start_date":"2015-01-01","end_date":"2018-09-30","data":[["2018-09-30",2901.5,52.34,130.39,252.439,3.0,2944.5129194578,53.115907704436,132.32295004932,32.6228911205],["2018-08-31",2857.82,51.89,127.75333333333,252.146,2.89,2903.555479266,52.720428095231,129.79784975768,32.390276880301],["2018-07-31",2793.64,51.44,125.11666666667,252.006,2.89,2839.9251892812,52.29226089855,127.18960684468,31.886366962159],["2018-06-30",2754.35,50.99,122.48,251.989,2.91,2800.1731263567,51.838302217557,124.51765553258,31.630556496455],["2018-05-31",2701.49,50.66,120.13333333333,251.588,2.976,2750.8111875864,51.58490120753,122.32661136461,31.243615074865],["2018-04-30",2653.63,50.33,117.78666666667,250.546,2.87,2713.3151215246,51.462016206605,120.43590997262,30.970179293325],["2018-03-31",2702.77,50.0,115.44,249.554,2.84,2774.5457779178,51.327818828791,118.50566811191,31.808409057643],["2018-02-28",2705.16,49.643333333333,113.58666666667,248.991,2.86,2783.2783925925,51.076911163456,116.86677128892,32.03538233925],["2018-01-31",2789.8,49.286666666667,111.73333333333,247.867,2.58,2883.3787928607,50.939898715844,115.48122581868,33.307343828031],["2017-12-31",2664.34,48.93,109.88,246.524,2.4,2768.7119778399,50.846767708215,114.18440293846,32.086132007706],["2017-11-30",2593.61,48.676666666667,108.94666666667,246.669,2.35,2693.6268919585,50.553775758202,113.14795637068,31.29891333388],["2017-10-31",2557.0,48.423333333333,108.01333333333,246.663,2.36,2655.6697042118,50.291896484272,112.18135979048,30.920393290334],["2017-09-30",2492.84,48.17,107.08,246.819,2.2,2587.3975149806,49.997167205523,111.14172024844,30.168114410679],["2017-08-31",2456.22,47.853333333333,106.06,245.519,2.21,2562.8872302144,49.931478826486,110.66590925753,29.914959397497],["2017-07-31",2454.1,47.536666666667,105.04,244.786,2.32,2568.3429837695,49.749588160679,109.92981011986,30.002220744019],["2017-06-30",2433.99,47.22,104.02,244.955,2.19,2545.5393875916,49.384085342206,108.78722061195,29.748503240633],["2017-05-31",2395.35,46.94,102.77666666667,244.733,2.3,2507.4009520069,49.135784201558,107.58440805899,29.313344980271],["2017-04-30",2359.31,46.66,101.53333333333,244.524,2.3,2471.7859389569,48.884433123129,106.37375574586,28.904245956275],["2017-03-31",2366.82,46.38,100.29,243.801,2.48,2487.0074615157,48.735183100151,105.3827406881,29.086921742465],["2017-02-28",2329.91,46.153333333333,98.376666666667,243.603,2.42,2450.2130769633,48.536424530897,103.4562687549,28.655106525184],["2017-01-31",2275.12,45.926666666667,96.463333333333,242.839,2.43,2400.1214199531,48.45000545629,101.76329713308,28.063573742124],["2016-12-31",2246.63,45.7,94.55,241.432,2.49,2383.8782004353,48.49184501226,100.32612573105,27.865098223924],["2016-11-30",2164.99,45.476666666667,92.73,241.353,2.14,2298.0026949634,48.27066293976,98.427147425141,26.850953531056],["2016-10-31",2143.02,45.253333333333,90.91,241.729,1.76,2271.1447214649,47.958894050776,96.34523552201,26.525143085071],["2016-09-30",2157.69,45.03,89.09,241.428,1.63,2289.5427262476,47.781705881256,94.534136730205,26.727873346479],["2016-08-31",2170.95,44.84,88.366666666667,240.849,1.56,2309.1508982288,47.694477660277,93.992016263302,26.948872433724],["2016-07-31",2148.9,44.65,87.643333333333,240.628,1.5,2287.7964664337,47.53600084986,93.308254598384,26.694003256096],["2016-06-30",2083.89,44.46,86.92,241.018,1.64,2214.9945027446,47.257127579683,92.388428457626,25.840372927671],["2016-05-31",2065.55,44.266666666667,86.76,240.229,1.81,2202.7115000166,47.206165783482,92.521241190697,25.69470992345],["2016-04-30",2075.54,44.073333333333,86.6,239.261,1.81,2222.3196911532,47.190146430049,92.72424778798,25.922337543674],["2016-03-31",2021.95,43.88,86.44,238.132,1.89,2175.2039979402,47.20589106042,92.991732526498,25.372298620188],["2016-02-29",1904.42,43.716666666667,86.47,237.111,1.78,2057.5877800903,47.232689805618,93.42456776573,24.00260677729],["2016-01-31",1918.6,43.553333333333,86.5,236.916,2.09,2074.6144044725,47.094950847558,93.533902838981,24.206167203878],["2015-12-31",2054.08,43.39,86.53,236.525,2.24,2224.7829278089,46.995896575415,93.721017070077,25.965424037124],["2015-11-30",2080.62,43.096666666667,87.906666666667,237.336,2.26,2245.8279922768,46.518682111016,94.886741792227,26.225851890972],["2015-10-31",2024.81,42.803333333333,89.283333333333,237.838,2.07,2180.9734222979,46.104539381848,96.169308258142,25.491441046067],["2015-09-30",1944.41,42.51,90.66,237.945,2.17,2093.4307689277,45.767992340667,97.608237723003,24.496752170486],["2015-08-31",2039.87,42.253333333333,92.076666666667,238.316,2.17,2192.7879220761,45.420835151647,98.979151892865,25.693658417058],["2015-07-31",2094.14,41.996666666667,93.493333333333,238.654,2.32,2247.9380311036,45.080989895413,100.35967970367,26.3811363364],["2015-06-30",2099.29,41.74,94.91,238.638,2.36,2253.6173464096,44.808477170442,101.88722013049,26.495895292785],["2015-05-31",2111.94,41.43,96.356666666667,237.805,2.2,2275.1389967621,44.631480362061,103.80257485124,26.806111379651],["2015-04-30",2094.86,41.12,97.803333333333,236.599,1.94,2268.2422722624,44.523320047845,105.89808151133,26.791371680192],["2015-03-31",2079.99,40.81,99.25,236.119,2.04,2256.7198666245,44.277490640313,107.68294403458,26.728605452928],["2015-02-28",2082.2,40.353333333333,100.27,234.722,1.98,2272.5632823084,44.042600927906,109.43709553216,26.995513699383],["2015-01-31",2028.18,39.896666666667,101.29,233.707,1.88,2223.2183358864,43.733298264494,111.03047325283,26.492295420383]],"collapse":null,"order":null,"database_id":175}}

 var datamodel = {
  "mkt":[],
  "confidence":[],
  "homes":[],
  "combined":[]
 }
 var tObject={};

  data.dataset.data.forEach(element => {
   tObject['date']=element[0];
   tObject['spx'] = element[1];
   tObject['rate']=element[5];
   datamodel['mkt'].push(tObject); //creating an array of objects
   tObject={};
 });
 
 /*
 datamodel.mkt.forEach(element => {
  datamodel["combined"].push(element);  
 });*/
 
 for(var i=0;i<datamodel.mkt.length; i++)
 {
  datamodel.combined[i] = datamodel.mkt[i];
 }
 document.getElementById("foo").innerHTML = "Length of datamodel.mkt = " + datamodel.mkt.length + "<br> Length of datamodel.combined = " + datamodel.combined.length;
 //console.log(datamodel);
}

<html>
 <head></head>
 <body onload="setData()">
  <div id="foo"></div>
 </body>
</html>

Thank you very much Sumir. I see the code runs on the snippet button. I cannot seem to replicate it on my side. It continues to show zero on the actual HTML side. — alf, Aug 24 '19 at 23:56
I just used the var data equal to the actual string representing the json object and it works. The array seems to work well this way and the length property gets created successfully. However, then running d3.json and running it from there, the array does not seem to have any length property. This is extremely weird to me. I am a python programmer, but trying to explore visualization via JS, and it is driving me mad:) — alf, Aug 25 '19 at 00:02
weirdest thing: now it works when the code is completely encapsulated in a function, and not separate. I cannot call the length attribute outside of the function — alf, Aug 25 '19 at 00:21
Can you share this code? It might be due to scope and closures properties in JavaScript. — Sumir Mathur, Aug 26 '19 at 04:55
newbie on so question: how do i post the code on this same thread? — alf, Aug 27 '19 at 03:01

Abhishek Kumar · Answer 2 · 2019-08-26T13:32:30.833

You can use map() or forEach() to get your work done. In "forEach(), you are pushing the objects, but the array is getting updated only by the last object. You can do something like this:

let data  ={
  "dataset": {
      "id": 539984,
      "dataset_code": "SPCOMP",
      "database_code": "YALE",
      "name": "S&P Composite",
      "description": "This data set consists of monthly stock price, dividends, and earnings data and the consumer price index (to allow conversion to real values), all starting January 1871. Further info at http://www.econ.yale.edu/~shiller/data.htm.",
      "refreshed_at": "2019-08-24T02:51:26.805Z",
      "newest_available_date": "2019-08-31",
      "oldest_available_date": "1871-01-31",
      "column_names": [
          "Year",
          "S&P Composite",
          "Dividend",
          "Earnings",
          "CPI",
          "Long Interest Rate",
          "Real Price",
          "Real Dividend",
          "Real Earnings",
          "Cyclically Adjusted PE Ratio"
      ],
      "frequency": "monthly",
      "type": "Time Series",
      "premium": false,
      "limit": null,
      "transform": null,
      "column_index": null,
      "start_date": "2015-01-01",
      "end_date": "2018-09-30",
      "data": [
          [
              "2018-09-30",
              2901.5,
              52.34,
              130.39,
              252.439,
              3.0,
              2944.5129194578,
              53.115907704436,
              132.32295004932,
              32.6228911205
          ],
          [
              "2018-08-31",
              2857.82,
              51.89,
              127.75333333333,
              252.146,
              2.89,
              2903.555479266,
              52.720428095231,
              129.79784975768,
              32.390276880301
          ],
          [
              "2018-07-31",
              2793.64,
              51.44,
              125.11666666667,
              252.006,
              2.89,
              2839.9251892812,
              52.29226089855,
              127.18960684468,
              31.886366962159
          ],
          [
              "2018-06-30",
              2754.35,
              50.99,
              122.48,
              251.989,
              2.91,
              2800.1731263567,
              51.838302217557,
              124.51765553258,
              31.630556496455
          ],
          [
              "2018-05-31",
              2701.49,
              50.66,
              120.13333333333,
              251.588,
              2.976,
              2750.8111875864,
              51.58490120753,
              122.32661136461,
              31.243615074865
          ],
          [
              "2018-04-30",
              2653.63,
              50.33,
              117.78666666667,
              250.546,
              2.87,
              2713.3151215246,
              51.462016206605,
              120.43590997262,
              30.970179293325
          ],
          [
              "2018-03-31",
              2702.77,
              50.0,
              115.44,
              249.554,
              2.84,
              2774.5457779178,
              51.327818828791,
              118.50566811191,
              31.808409057643
          ],
          [
              "2018-02-28",
              2705.16,
              49.643333333333,
              113.58666666667,
              248.991,
              2.86,
              2783.2783925925,
              51.076911163456,
              116.86677128892,
              32.03538233925
          ],
          [
              "2018-01-31",
              2789.8,
              49.286666666667,
              111.73333333333,
              247.867,
              2.58,
              2883.3787928607,
              50.939898715844,
              115.48122581868,
              33.307343828031
          ],
          [
              "2017-12-31",
              2664.34,
              48.93,
              109.88,
              246.524,
              2.4,
              2768.7119778399,
              50.846767708215,
              114.18440293846,
              32.086132007706
          ],
          [
              "2017-11-30",
              2593.61,
              48.676666666667,
              108.94666666667,
              246.669,
              2.35,
              2693.6268919585,
              50.553775758202,
              113.14795637068,
              31.29891333388
          ],
          [
              "2017-10-31",
              2557.0,
              48.423333333333,
              108.01333333333,
              246.663,
              2.36,
              2655.6697042118,
              50.291896484272,
              112.18135979048,
              30.920393290334
          ],
          [
              "2017-09-30",
              2492.84,
              48.17,
              107.08,
              246.819,
              2.2,
              2587.3975149806,
              49.997167205523,
              111.14172024844,
              30.168114410679
          ],
          [
              "2017-08-31",
              2456.22,
              47.853333333333,
              106.06,
              245.519,
              2.21,
              2562.8872302144,
              49.931478826486,
              110.66590925753,
              29.914959397497
          ],
          [
              "2017-07-31",
              2454.1,
              47.536666666667,
              105.04,
              244.786,
              2.32,
              2568.3429837695,
              49.749588160679,
              109.92981011986,
              30.002220744019
          ],
          [
              "2017-06-30",
              2433.99,
              47.22,
              104.02,
              244.955,
              2.19,
              2545.5393875916,
              49.384085342206,
              108.78722061195,
              29.748503240633
          ],
          [
              "2017-05-31",
              2395.35,
              46.94,
              102.77666666667,
              244.733,
              2.3,
              2507.4009520069,
              49.135784201558,
              107.58440805899,
              29.313344980271
          ],
          [
              "2017-04-30",
              2359.31,
              46.66,
              101.53333333333,
              244.524,
              2.3,
              2471.7859389569,
              48.884433123129,
              106.37375574586,
              28.904245956275
          ],
          [
              "2017-03-31",
              2366.82,
              46.38,
              100.29,
              243.801,
              2.48,
              2487.0074615157,
              48.735183100151,
              105.3827406881,
              29.086921742465
          ],
          [
              "2017-02-28",
              2329.91,
              46.153333333333,
              98.376666666667,
              243.603,
              2.42,
              2450.2130769633,
              48.536424530897,
              103.4562687549,
              28.655106525184
          ],
          [
              "2017-01-31",
              2275.12,
              45.926666666667,
              96.463333333333,
              242.839,
              2.43,
              2400.1214199531,
              48.45000545629,
              101.76329713308,
              28.063573742124
          ],
          [
              "2016-12-31",
              2246.63,
              45.7,
              94.55,
              241.432,
              2.49,
              2383.8782004353,
              48.49184501226,
              100.32612573105,
              27.865098223924
          ],
          [
              "2016-11-30",
              2164.99,
              45.476666666667,
              92.73,
              241.353,
              2.14,
              2298.0026949634,
              48.27066293976,
              98.427147425141,
              26.850953531056
          ],
          [
              "2016-10-31",
              2143.02,
              45.253333333333,
              90.91,
              241.729,
              1.76,
              2271.1447214649,
              47.958894050776,
              96.34523552201,
              26.525143085071
          ],
          [
              "2016-09-30",
              2157.69,
              45.03,
              89.09,
              241.428,
              1.63,
              2289.5427262476,
              47.781705881256,
              94.534136730205,
              26.727873346479
          ],
          [
              "2016-08-31",
              2170.95,
              44.84,
              88.366666666667,
              240.849,
              1.56,
              2309.1508982288,
              47.694477660277,
              93.992016263302,
              26.948872433724
          ],
          [
              "2016-07-31",
              2148.9,
              44.65,
              87.643333333333,
              240.628,
              1.5,
              2287.7964664337,
              47.53600084986,
              93.308254598384,
              26.694003256096
          ],
          [
              "2016-06-30",
              2083.89,
              44.46,
              86.92,
              241.018,
              1.64,
              2214.9945027446,
              47.257127579683,
              92.388428457626,
              25.840372927671
          ],
          [
              "2016-05-31",
              2065.55,
              44.266666666667,
              86.76,
              240.229,
              1.81,
              2202.7115000166,
              47.206165783482,
              92.521241190697,
              25.69470992345
          ],
          [
              "2016-04-30",
              2075.54,
              44.073333333333,
              86.6,
              239.261,
              1.81,
              2222.3196911532,
              47.190146430049,
              92.72424778798,
              25.922337543674
          ],
          [
              "2016-03-31",
              2021.95,
              43.88,
              86.44,
              238.132,
              1.89,
              2175.2039979402,
              47.20589106042,
              92.991732526498,
              25.372298620188
          ],
          [
              "2016-02-29",
              1904.42,
              43.716666666667,
              86.47,
              237.111,
              1.78,
              2057.5877800903,
              47.232689805618,
              93.42456776573,
              24.00260677729
          ],
          [
              "2016-01-31",
              1918.6,
              43.553333333333,
              86.5,
              236.916,
              2.09,
              2074.6144044725,
              47.094950847558,
              93.533902838981,
              24.206167203878
          ],
          [
              "2015-12-31",
              2054.08,
              43.39,
              86.53,
              236.525,
              2.24,
              2224.7829278089,
              46.995896575415,
              93.721017070077,
              25.965424037124
          ],
          [
              "2015-11-30",
              2080.62,
              43.096666666667,
              87.906666666667,
              237.336,
              2.26,
              2245.8279922768,
              46.518682111016,
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              "2015-05-31",
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          [
              "2015-03-31",
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          [
              "2015-02-28",
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          [
              "2015-01-31",
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      ],
      "collapse": null,
      "order": null,
      "database_id": 175
  }
  }
  var datamodel = {
  "mkt":[],
  "confidence":[],
  "homes":[],
  "combined":[]
  }

  var tObject={};

  (data['dataset']['data']).map((mkt, index) => {
  tObject['date'] = mkt[0];
  tObject['spx'] = mkt[1];
  tObject['rate'] = mkt[5];
  datamodel['mkt'].push(JSON.parse(JSON.stringify(tObject)))
 })
 console.log(datamodel['mkt'].length)

data is the JSON data which I got after hitting your API. I hope it helps.

Object with Key:Value where every Value is an Array of Objects - cannot iterate

2 Answers2