为什么这个折线图没有绘制？ （d3js）

Question

数据的格式如下：

[
    {y: 17.0, x: '2015-07-23 00:02:41'}, 
    {y: 17.0, x: '2015-07-23 00:03:41'}, 
    {y: 15.0, x: '2015-07-23 01:21:44'}, 
    {y: 23.0, x: '2015-07-23 02:50:48'}, 
    {y: 21.0, x: '2015-07-23 02:51:48'}, 
    {y: 28.0, x: '2015-07-23 02:52:48'}, 
    {y: 24.0, x: '2015-07-23 02:53:48'}, 
    {y: 27.0, x: '2015-07-23 02:54:48'}, 
    {y: 18.0, x: '2015-07-23 02:55:48'}, 
    {y: 28.0, x: '2015-07-23 02:56:48'}
]

我试图根据这些数据绘制折线图;但每次我尝试它都是空白的;这就是我正在做的事情：

var margin = {top: 20, right: 20, bottom: 30, left: 50},
width = 960 - margin.left - margin.right,
height = 500 - margin.top - margin.bottom;

var parseDate = d3.time.format("%Y-%m-%d %H:%M:%S").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 vline = d3.svg.line()
    .x(function(d, i) { return x(parseDate(d.x)); })
    .y(function(d, i) { return y(d.y); });

// add canvas
var svg = d3.select(".swatch").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 + ")");

x.domain(d3.extent(data, function(d) { return d.x; }));
y.domain([0, d3.max(data, function(d) { return d.y; })]);

// draw line
svg.append("path")
  .attr("class", "line")
  .attr("d", vline(data));

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

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

使用console.log打印时，字段输出正确（来自var vline = d3.svg.line()...，但该行永远不会被绘制。

知道为什么它没有画线？

Answer 1

$(document).ready(function () {
	data =[
    {y: 17.0, x: '2015-07-23 00:02:41'}, 
    {y: 17.0, x: '2015-07-23 00:03:41'}, 
    {y: 15.0, x: '2015-07-23 01:21:44'}, 
    {y: 23.0, x: '2015-07-23 02:50:48'}, 
    {y: 21.0, x: '2015-07-23 02:51:48'}, 
    {y: 28.0, x: '2015-07-23 02:52:48'}, 
    {y: 24.0, x: '2015-07-23 02:53:48'}, 
    {y: 27.0, x: '2015-07-23 02:54:48'}, 
    {y: 18.0, x: '2015-07-23 02:55:48'}, 
    {y: 28.0, x: '2015-07-23 02:56:48'}
];
		var margin = {top: 20, right: 20, bottom: 30, left: 50},
width = 960 - margin.left - margin.right,
height = 500 - margin.top - margin.bottom;

var parseDate = d3.time.format("%Y-%m-%d %H:%M:%S").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 vline = d3.svg.line()
    .x(function(d, i) { return x(parseDate(d.x)); })
    .y(function(d, i) { return y(d.y); });

// add canvas
var svg = d3.select(".swatch").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 + ")");

x.domain(d3.extent(data, function(d) { return parseDate(d.x); }));
y.domain([0, d3.max(data, function(d) { return d.y; })]);

// draw line
svg.append("path")
  .attr("class", "line")
  .attr("d", vline(data));

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

// y axis
svg.append("g")
  .attr("class", "y axis")
  .call(yAxis);
    });

path {
	stroke: black;
	fill: none;
}

<script src="https://ajax.googleapis.com/ajax/libs/jquery/2.1.1/jquery.min.js"></script>
<script src="https://cdnjs.cloudflare.com/ajax/libs/d3/3.4.11/d3.min.js"></script>
<div id="dectree" class='swatch'></div>

这是工作.....