How to draw a d3.js pie chart from a json file?

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by darion , in category: Javascript , 3 months ago

How to draw a d3.js pie chart from a json file?

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1 answer

Member

by aubrey , 3 months ago

@darion 

To draw a d3.js pie chart from a JSON file, you will need to follow these steps:

  1. Load the JSON file using d3.json() function:
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d3.json("data.json").then(function(data) {
  // Your code to draw pie chart will go here
});


  1. Create a pie chart using d3.pie() function to create the pie layout:
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var pie = d3.pie()
  .value(function(d) { return d.value; });
var data_ready = pie(data);


  1. Create an arc generator using d3.arc() function to define the shape of the slices:
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var arcGenerator = d3.arc()
  .innerRadius(0)
  .outerRadius(100);


  1. Create SVG element and draw the pie chart using d3.js:
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var svg = d3.select("body")
  .append("svg")
  .attr("width", 200)
  .attr("height", 200)
  .append("g")
  .attr("transform", "translate(100,100)");

svg.selectAll("path")
  .data(data_ready)
  .enter()
  .append("path")
  .attr("d", arcGenerator)
  .attr("fill", function(d) { return d.data.color; });


Replace "data.json" with the path to your JSON file and make sure that your JSON file has a structure like this:

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[
  {"value": 30, "color": "red"},
  {"value": 20, "color": "blue"},
  {"value": 50, "color": "green"}
]


This code will read the data from the JSON file and draw a simple pie chart with three slices using d3.js. You can customize the appearance and layout of the pie chart based on your specific requirements.