d3 Pie chart with one object key /value

Question

Hello I am quite new with d3 and javascript. I am trying to display a pie chart with one object filled with mutiple keys and values.

Here my object :

dataset Object { $Allied Health Professions, Dentistry, Nursing and Pharmacy: 4, $Psychology, Psychiatry and Neuroscience: 4, $Biological Sciences: 4, $General Engineering: 4, $Architecture, Built Environment and Planning: 4, $Geography, Environmental Studies and Archaeology: 4, $Business and Management Studies: 4, $Law: 4, $Social Work and Social Policy: 4, $Education: 4, 5 de plus… }

My code is quite long and in mutiple files so I don't think it's relevant to link it.

I succeed to load a pie chart with a simple array but I do not know how to access the values here.

https://stackoverflow.com/questions/8312459/iterate-through-object-properties — IrkenInvader, Nov 14 '17 at 23:12

score 3 · Accepted Answer · answered Nov 14 '17 at 23:53

D3 data method accepts 3 things:

An array;
A function;
Nothing;

Therefore, you have to convert that object in an array of objects, with a specific property for the category and a property for the value. For instance:

var obj = {
  "Allied Health Professions, Dentistry, Nursing and Pharmacy": 4,
  "Psychology, Psychiatry and Neuroscience": 4,
  "Biological Sciences": 4,
  "General Engineering": 4,
  "Architecture, Built Environment and Planning": 4
};
var data = [];
for (var key in obj) {
  data.push({
    name: key,
    value: obj[key]
  })
};
console.log(data)

Here is a basic demo with a portion of your object:

var obj = {
  "Allied Health Professions, Dentistry, Nursing and Pharmacy": 4,
  "Psychology, Psychiatry and Neuroscience": 4,
  "Biological Sciences": 4,
  "General Engineering": 4,
  "Architecture, Built Environment and Planning": 4
};
var data = [];
for (var key in obj) {
  data.push({
    name: key,
    value: obj[key]
  })
};
var arc = d3.arc().outerRadius(100).innerRadius(0);
var pie = d3.pie().value(function(d) {
  return d.value
});
var colors = d3.scaleOrdinal(d3.schemeCategory10)
var svg = d3.select("svg")
  .append("g")
  .attr("transform", "translate(100,100)")
svg.selectAll(null)
  .data(pie(data))
  .enter()
  .append("path")
  .attr("d", arc)
  .style("fill", function(d, i) {
    return colors(i)
  })

<script src="https://d3js.org/d3.v4.min.js"></script>
<svg width="200" height="200"></svg>

d3 Pie chart with one object key /value

1 Answers1