Menu
I am trying to adapt a simple scatterplot program in D3 to accept a CSV file. When I use the data in the file it works just fine, but when I try to load the CSV file it simply won't work. Is there something simple I am missing? The contents of the CSV file "datatest.csv" are the same as the dataset in the code. I have checked that the browser is loading the data, and it seems to all be there. I figure I'm simply missing a step.
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="utf-8">
<title>D3 Demo: Linear scales</title>
<script type="text/javascript" src="../d3/d3.v3.js"></script>
<style type="text/css">
/* No style rules here yet */
</style>
</head>
<body>
<script type="text/javascript">
//Width and height
var w = 900;
var h = 500;
var padding = 20;
var dataset = [];
// var dataset = [
// [5, 20], [480, 90], [250, 50], [100, 33], [330, 95],
// [410, 12], [475, 44], [25, 67], [85, 21], [220, 88],
// [600, 150]
// ];
d3.csv("datatest.csv", function(data) {
dataset=data
});
//Create scale functions
var xScale = d3.scale.linear()
.domain([0, d3.max(dataset, function(d) { return d[0]; })])
.range([padding, w - padding * 2]);
var yScale = d3.scale.linear()
.domain([0, d3.max(dataset, function(d) { return d[1]; })])
.range([h - padding, padding]);
var rScale = d3.scale.linear()
.domain([0, d3.max(dataset, function(d) { return d[1]; })])
.range([2, 5]);
//Create SVG element
var svg = d3.select("body")
.append("svg")
.attr("width", w)
.attr("height", h);
svg.selectAll("circle")
.data(dataset)
.enter()
.append("circle")
.attr("cx", function(d) {
return xScale(d[0]);
})
.attr("cy", function(d) {
return yScale(d[1]);
})
.attr("r", function(d) {
return rScale(d[1]);
});
</script>
</body>
</html>
This is the content of the CSV file:
x-coordinate, y-coordinate
5,20
480,90
250,50
100,33
330,95
410,12
475,44
25,67
85,21
220,88
600,150
538
IMPORTANT:
While the answer here works, there's a builtin method d3.csv.parseRows(), which achieves the same result. For that, see @ryanmt's answer (also on this page). However, keep in mind that regardless of the method you use, if your CSV has numbers in it then you'll need to convert them from strings to javascript Numbers. You can do it by prefixing the parsed values with a +. For example, in the solution I provided here — which doesn't use parseRows() — that conversion is achieved via +d["x-coordinate"].
THE ANSWER:
The CSV parser produces an array of objects, rather than the array of arrays that you need. It looks like this:
[
{"x-coordinate":"5"," y-coordinate":"20"},
{"x-coordinate":"480"," y-coordinate":"90"},
{"x-coordinate":"250"," y-coordinate":"50"},
{"x-coordinate":"100"," y-coordinate":"33"},
...
]
To transform it, you need to use a map() function:
d3.csv("datatest.csv", function(data) {
dataset = data.map(function(d) { return [ +d["x-coordinate"], +d["y-coordinate"] ]; });
});
(Note, map() is not available in older IE. If that matters, then there are plenty of workarounds with d3, jQuery, etc)
186
D3 provides a builtin for this very thing.
Instead of calling .parse() on your data, call .parseRows. This provides just the data as an Array, rather than an Object (based upon the header line).
see the Documentation.
37
If you love us? You can donate to us via Paypal or buy me a coffee so we can maintain and grow! Thank you!
Donate Us With
