带有键的对象：值，其中每个值都是对象数组 - 不能迭代 [重复]

【问题标题】：Object with Key:Value where every Value is an Array of Objects - cannot iterate [duplicate]带有键的对象：值，其中每个值都是对象数组 - 不能迭代 [重复]
【发布时间】：2019-08-24 02:38:29
【问题描述】：

我正在通过d3.json 下载数据，同时创建一个包含下载数据的每条记录的对象。每个对象都将存储在一个数组中。我失去了遍历数组的能力。

我尝试过使用多维数组，但仍然无法遍历创建的对象。 

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={};
    });
});

我重复上面的代码来填充其他数据集"confidence, homes" 我需要在下载datamodel 后进行迭代，并更新"combined" 以便获得更多统计信息，例如每个日期的变化、比率。 例如：在任何浏览器中调试控制台，我可以通过datamodel.mkt访问datamodel变量

调试控制台允许我迭代对象，不知道为什么在 JS 文件中运行的代码不允许我迭代而不是获取数组的长度。我很迷茫。

【问题讨论】：

    标签： javascript arrays object d3.js iteration


    【解决方案1】：

    我在浏览器中点击 API 并将数据复制到我的 js 文件中。我在 HTML onload 中调用此函数。此函数的一半执行您的代码在 datamodel.mkt 中填充数据所做的工作

    然后循环遍历 datamodel.mkt 中的数据并复制 datamodel.combined 中的元素

    请注意，注释的 forEach 循环也有效。您可以取消注释 console.log 以在控制台中查看数据模型对象

    希望这会有所帮助。 

    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>

    【讨论】：

    • 非常感谢苏米尔。我看到代码在 sn-p 按钮上运行。我似乎无法在我身边复制它。它在实际的 HTML 端继续显示为零。
    • 我只是使用了 var 数据，它等于表示 json 对象的实际字符串，它可以工作。该数组似乎以这种方式运行良好，并且成功创建了长度属性。但是，然后运行 ​​d3.json 并从那里运行它，该数组似乎没有任何长度属性。这对我来说非常奇怪。我是一名 python 程序员，但试图通过 JS 探索可视化，这让我发疯:)
    • 最奇怪的是：现在它可以在代码完全封装在一个函数中而不是分开时工作。我不能在函数之外调用长度属性
    • 你能分享这段代码吗？这可能是由于 JavaScript 中的作用域和闭包属性造成的。
    • 新手问题：我如何在同一个线程上发布代码？
    【解决方案2】：

    您可以使用 ma​​p() 或 forEach() 来完成您的工作。在 "forEach() 中，您正在推送对象，但数组仅由最后一个对象更新。您可以执行以下操作：

    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,
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              1.89,
              2175.2039979402,
              47.20589106042,
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          ],
          [
              "2016-02-29",
              1904.42,
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              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,
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          ],
          [
              "2015-12-31",
              2054.08,
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              2.24,
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          ],
          [
              "2015-11-30",
              2080.62,
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          ],
          [
              "2015-10-31",
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          [
              "2015-09-30",
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          ],
          [
              "2015-08-31",
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          ],
          [
              "2015-07-31",
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          ],
          [
              "2015-06-30",
              2099.29,
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          ],
          [
              "2015-05-31",
              2111.94,
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          ],
          [
              "2015-04-30",
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              44.523320047845,
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          ],
          [
              "2015-03-31",
              2079.99,
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              2.04,
              2256.7198666245,
              44.277490640313,
              107.68294403458,
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          ],
          [
              "2015-02-28",
              2082.2,
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              100.27,
              234.722,
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              2272.5632823084,
              44.042600927906,
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          ],
          [
              "2015-01-31",
              2028.18,
              39.896666666667,
              101.29,
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              1.88,
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              26.492295420383
          ]
      ],
      "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 是我在点击你的 API 后得到的 JSON 数据。希望对你有帮助。

    【讨论】：

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