问题
I'm trying to make a bar chart with d3, and for this I'm following this tutorial d3noob chart, everything looks good but I'm unable to load the data from a JSON inside a variable instead of load from a JSON file, i've managed to load the json to a var but I have no idea of how to iterate the data and create the bars. The code:
<!DOCTYPE html>
<meta charset="utf-8">
<head>
<style>
.axis {
font: 10px sans-serif;
}
.axis path,
.axis line {
fill: none;
stroke: #000;
shape-rendering: crispEdges;
}
</style>
</head>
<body>
<script src="http://d3js.org/d3.v3.min.js"></script>
<script>
var jdata = [
{
"date": "2013-01",
"value": "53"
},
{
"date": "2013-02",
"value": "165"
},
{
"date": "2013-03",
"value": "269"
},
{
"date": "2013-04",
"value": "344"
},
{
"date": "2013-05",
"value": "376"
},
{
"date": "2013-06",
"value": "410"
},
{
"date": "2013-07",
"value": "421"
},
{
"date": "2013-08",
"value": "405"
},
{
"date": "2013-09",
"value": "376"
},
{
"date": "2013-10",
"value": "359"
},
{
"date": "2013-11",
"value": "392"
},
{
"date": "2013-12",
"value": "433"
},
{
"date": "2014-01",
"value": "455"
},
{
"date": "2014-02",
"value": "478"
}
];
// console.log(jdata);
root = JSON.parse( jdata );
var margin = {top: 20, right: 20, bottom: 70, left: 40},
width = 600 - margin.left - margin.right,
height = 300 - margin.top - margin.bottom;
// Parse the date / time
var parseDate = d3.time.format("%Y-%m").parse;
var x = d3.scale.ordinal().rangeRoundBands([0, width], .05);
var y = d3.scale.linear().range([height, 0]);
var xAxis = d3.svg.axis()
.scale(x)
.orient("bottom")
.tickFormat(d3.time.format("%Y-%m"));
var yAxis = d3.svg.axis()
.scale(y)
.orient("left")
.ticks(10);
var svg = d3.select("body").append("svg")
.data(root)
.attr("width", width + margin.left + margin.right)
.attr("height", height + margin.top + margin.bottom)
.append("g")
.attr("transform","translate(" + margin.left + "," + margin.top + ")");
//d3.json
//d3.csv("bar-data.csv", function(error, data) {
//d3.selectAll('g').data(function(data){
data.forEach(function(d) {
d.date = parseDate(d.date);
d.value = +d.value;
});
x.domain(data.map(function(d) { return d.date; }));
y.domain([0, d3.max(data, function(d) { return d.value; })]);
svg.append("g")
.attr("class", "x axis")
.attr("transform", "translate(0," + height + ")")
.call(xAxis)
.selectAll("text")
.style("text-anchor", "end")
.attr("dx", "-.8em")
.attr("dy", "-.55em")
.attr("transform", "rotate(-90)" );
svg.append("g")
.attr("class", "y axis")
.call(yAxis)
.append("text")
.attr("transform", "rotate(-90)")
.attr("y", 6)
.attr("dy", ".71em")
.style("text-anchor", "end")
.text("Value ($)");
svg.selectAll("bar")
.data(data)
.enter().append("rect")
.style("fill", "steelblue")
.attr("x", function(d) { return x(d.date); })
.attr("width", x.rangeBand())
.attr("y", function(d) { return y(d.value); })
.attr("height", function(d) { return height - y(d.value); });
});
</script>
</body>
It's here too: jsfiddle.
回答1:
See my comments in the code...
var jdata = [
{
"date": "2013-01",
"value": "53"
},
{
"date": "2013-02",
"value": "165"
},
{
"date": "2013-03",
"value": "269"
},
{
"date": "2013-04",
"value": "344"
},
{
"date": "2013-05",
"value": "376"
},
{
"date": "2013-06",
"value": "410"
},
{
"date": "2013-07",
"value": "421"
},
{
"date": "2013-08",
"value": "405"
},
{
"date": "2013-09",
"value": "376"
},
{
"date": "2013-10",
"value": "359"
},
{
"date": "2013-11",
"value": "392"
},
{
"date": "2013-12",
"value": "433"
},
{
"date": "2014-01",
"value": "455"
},
{
"date": "2014-02",
"value": "478"
}
],
//root = JSON.parse(jdata),
//***EDIT*** jdata is not a string as required by JSON.parse
//it's already well formed so just use it
data = jdata,
margin = {top: 20, right: 20, bottom: 70, left: 40},
width = 600 - margin.left - margin.right,
height = 300 - margin.top - margin.bottom,
// Parse the date / time
//***a better comment would be "for parsing the date and time"...
parseDate = d3.time.format("%Y-%m").parse,
x = d3.scale.ordinal().rangeRoundBands([0, width], .05),
y = d3.scale.linear().range([height, 0]),
xAxis = d3.svg.axis()
.scale(x)
.orient("bottom")
.tickFormat(d3.time.format("%Y-%m")),
yAxis = d3.svg.axis()
.scale(y)
.orient("left")
.ticks(10),
svg = d3.select("body").append("svg")
//***EDIT***
//the data method returns the enter collection and your not ready for it yet...
//.data(root)
.attr("width", width + margin.left + margin.right)
.attr("height", height + margin.top + margin.bottom)
.append("g")
.attr("transform","translate(" + margin.left + "," + margin.top + ")");
//d3.json
//d3.csv("bar-data.csv", function(error, data) {
//d3.selectAll('g').data(function(data){
data.forEach(function (d) {
//NOW is parsing the date and time
d.date = parseDate(d.date);
d.value = +d.value;
});
x.domain(data.map(function(d) { return d.date; }));
y.domain([0, d3.max(data, function(d) { return d.value; })]);
svg.append("g")
.attr("class", "x axis")
.attr("transform", "translate(0," + height + ")")
.call(xAxis)
.selectAll("text")
.style("text-anchor", "end")
.attr("dx", "-.8em")
.attr("dy", "-.55em")
.attr("transform", "rotate(-90)" );
svg.append("g")
.attr("class", "y axis")
.call(yAxis)
.append("text")
.attr("transform", "rotate(-90)")
.attr("y", 6)
.attr("dy", ".71em")
.style("text-anchor", "end")
.text("Value ($)");
svg.selectAll("bar")
.data(data)
.enter().append("rect")
.style("fill", "steelblue")
.attr("x", function(d) { return x(d.date); })
.attr("width", x.rangeBand())
.attr("y", function(d) { return y(d.value); })
.attr("height", function(d) { return height - y(d.value); });
//You forgot to comment this out...
// });
</script>
来源：https://stackoverflow.com/questions/29618805/convert-a-d3-chart-to-load-data-from-json-inside-a-variable