javascript - 带有键的对象：值，其中每个值都是对象数组 - 不能迭代

Question

我正在通过d3.json何时创建一个包含下载数据的每条记录的对象来下载数据。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" 我需要在下载后迭代datamodel并更新，"combined"以便我可以获得更多统计信息，比如每个日期的变化、比率。例如：要在任何浏览器中调试控制台，我可以datamodel通过 datamodel.mkt

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。

标签： javascriptarraysobjectd3.jsiteration

Answer 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 中调用这个函数。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

然后它遍历 datamodel.mkt 中存在的数据并复制 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

希望这可以帮助。

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>