D3中的折线图动态数据更新

时间:2014-05-16 14:29:17

标签: javascript d3.js

我一直在研究"简单图表" D3提示和技巧书中的示例:https://leanpub.com/D3-Tips-and-Tricks/read

我正在研究动态更新数据部分,但它不起作用,我无法弄清楚原因。正在读取备用数据,正在调整X和Y轴,但值行本身永远不会更新。我正在使用D3的v3.4.6并使用最新的Firefox和Chrome进行测试。有人能帮我发现错误吗?

示例HTML:

<!DOCTYPE html>
<meta charset="utf-8">
<style>
body { font: 12px Arial;}

path {
    stroke: steelblue;
    stroke-width: 2;
    fill: none;
}

.axis path,
.axis line {
    fill: none;
    stroke: grey;
    stroke-width: 1;
    shape-rendering: crispEdges;
}
</style>
<body>
<script type="text/javascript" src="d3/d3.js"></script>

<script>
var margin = {top: 30, right: 20, bottom: 30, left: 50},
    width = 600 - margin.left - margin.right,
    height = 270 - margin.top - margin.bottom;

var parseDate = d3.time.format("%d-%b-%y").parse;

var x = d3.time.scale().range([0, width]);
var y = d3.scale.linear().range([height, 0]);

var xAxis = d3.svg.axis().scale(x)
    .orient("bottom").ticks(5);

var yAxis = d3.svg.axis().scale(y)
    .orient("left").ticks(5);

var valueline = d3.svg.line()
    .x(function(d) { return x(d.date); })
    .y(function(d) { return y(d.close); });

var svg = d3.select("body")
    .append("svg")
    .attr("width", width + margin.left + margin.right)
    .attr("height", height + margin.top + margin.bottom)
    .append("g")
    .attr("transform", "translate(" + margin.left + "," + margin.top + ")");

// Get the data
d3.csv("simple.csv", function(error, data) {
    data.forEach(function(d) {
        d.date = parseDate(d.date);
        d.close = +d.close;
    });

    // Scale the range of the data
    x.domain(d3.extent(data, function(d) { return d.date; }));
    y.domain([0, d3.max(data, function(d) { return d.close; })]);

    svg.append("path")          // Add the valueline path.
        .attr("d", valueline(data));

    svg.append("g")                     // Add the X Axis
        .attr("class", "x axis")
        .attr("transform", "translate(0," + height + ")")
        .call(xAxis);

    svg.append("g")                     // Add the Y Axis
        .attr("class", "y axis")
        .call(yAxis);

});

function updateData() {

    // Get the data again
    d3.csv("simple-alt.csv", function(error, data) {
        data.forEach(function(d) {
                d.date = parseDate(d.date);
                d.close = +d.close;
            });

        // Scale the range of the data again
        x.domain(d3.extent(data, function(d) { return d.date; }));
        y.domain([0, d3.max(data, function(d) { return d.close; })]);

    // Select the section we want to apply our changes to
    var svg = d3.select("body").transition();

    // Make the changes
    svg.select(".line")   // change the line
        .duration(750)
        .attr("d", valueline(data));
    svg.select(".x.axis") // change the x axis
        .duration(750)
        .call(xAxis);
    svg.select(".y.axis") // change the y axis
        .duration(750)
        .call(yAxis);

    });
}

</script>

<div id="option">
    <input name="updateButton"
           type="button"
           value="Update"
           onclick="updateData()"
    />
</div>
</body>

示例数据:

date,close
1-May-12,58.13
30-Apr-12,53.98
27-Apr-12,67.00
26-Apr-12,89.70
25-Apr-12,99.00
24-Apr-12,130.28
23-Apr-12,166.70
20-Apr-12,234.98
19-Apr-12,345.44
18-Apr-12,443.34
17-Apr-12,543.70
16-Apr-12,580.13
13-Apr-12,605.23
12-Apr-12,622.77
11-Apr-12,626.20
10-Apr-12,628.44
9-Apr-12,636.23
5-Apr-12,633.68
4-Apr-12,624.31
3-Apr-12,629.32
2-Apr-12,618.63
30-Mar-12,599.55
29-Mar-12,609.86
28-Mar-12,617.62
27-Mar-12,614.48
26-Mar-12,606.98

示例替代数据:

date,close
10-May-12,99.55
8-May-12,76.86
6-May-12,67.62
4-May-12,64.48
2-May-12,60.98
1-May-12,58.13
30-Apr-12,53.98
27-Apr-12,67.00
26-Apr-12,89.70
25-Apr-12,99.00
24-Apr-12,90.28
23-Apr-12,106.70
20-Apr-12,94.98
19-Apr-12,85.44
18-Apr-12,73.34
17-Apr-12,53.70
16-Apr-12,50.13
13-Apr-12,65.23
12-Apr-12,62.77
11-Apr-12,66.20
10-Apr-12,68.44
9-Apr-12,66.23
5-Apr-12,63.68
4-Apr-12,64.31
3-Apr-12,69.32
2-Apr-12,61.63

1 个答案:

答案 0 :(得分:1)

您尚未将路径声明为类line。因此,您之后的选择svg.select(".line")为空。工作演示here