Question

为什么arr数据只在json函数中可用？第一个console.log返回数据，第二个是空数组？我是否需要结束第一次调用或以某种方式复制到动态数组？

 var inputURL;
    var start = "2016-09-01";  
    var end = "2016-09-06"; 
    var arr = [];
    var stock = ["AZN.L", "GOOGL", "AAPL"];

    var arrayLength = stock.length;
    for (var i = 0; i < arrayLength; i++) {
        itern(stock[i]);
    };


    function itern (stock) {

     inputURL = "http://query.yahooapis.com/v1/public/yql" +
        "?q=select%20*%20from%20yahoo.finance.historicaldata%20" +
        "where%20symbol%20%3D%20%22"
        + stock + "%22%20and%20startDate%20%3D%20%22"
        + start + "%22%20and%20endDate%20%3D%20%22"
        + end + "%22&format=json&env=store%3A%2F%2F"
        + "datatables.org%2Falltableswithkeys";


    // Get the data 
     d3.json(inputURL, function (error, data) {

        data.query.results.quote.forEach(function (d) {
            d.date = parseDate(d.Date);
           //  console.log(d.date);
            d.high = +d.High;
            d.low = +d.Low;
            arr.push({
                company: stock,
                date: d.date,
                high: d.high,
                low: d.low,
                sortable: true,
                resizeable: true
            });
        });

        console.log(arr);  //returns arr with data

    });
         console.log(arr);  // returns arr[]
    };

Answer 1

d3.json是一个异步函数，因此只有在执行回调后才会填充arr。您可以在回调中填充arr之后调用函数，如下所示：

    var dataAvailable = function() {
        console.log(arr);  
    };

    d3.json(inputURL, function (error, data) {

        data.query.results.quote.forEach(function (d) {
            d.date = parseDate(d.Date);
            //  console.log(d.date);
            d.high = +d.High;
            d.low = +d.Low;
            arr.push({
                company: stock,
                date: d.date,
                high: d.high,
                low: d.low,
                sortable: true,
                resizeable: true
            });
        });
        dataAvailable()
//        console.log(arr);  //returns arr with data

    });

全局数组不使用d3.json更新

1 个答案: