This post describes how to build a button that changes the input dataset of a barplot. You need to understand how to draw a basic barplot first. It is a good way to understand the enter() and exit functions of d3.
Important note: This example does not update the X and Y axis, it works only if the 2 datasets have the same groups and same Y range. See here for an upgraded version
buttons in the html part. When you click the button, a function called update() is triggered.update() function updates the value of the 3 groups<!DOCTYPE html>
<meta charset="utf-8">
<!-- Load d3.js -->
<script src="https://d3js.org/d3.v4.js"></script>
<!-- Add 2 buttons -->
<button onclick="update(data1)">Variable 1</button>
<button onclick="update(data2)">Variable 2</button>
<!-- Create a div where the graph will take place -->
<div id="my_dataviz"></div>
<script>
// create 2 data_set
var data1 = [
{group: "A", value: 4},
{group: "B", value: 16},
{group: "C", value: 8}
];
var data2 = [
{group: "A", value: 7},
{group: "B", value: 1},
{group: "C", value: 20}
];
// set the dimensions and margins of the graph
var margin = {top: 30, right: 30, bottom: 70, left: 60},
width = 460 - margin.left - margin.right,
height = 400 - margin.top - margin.bottom;
// append the svg object to the body of the page
var svg = d3.select("#my_dataviz")
.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 axis
var x = d3.scaleBand()
.range([ 0, width ])
.domain(data1.map(function(d) { return d.group; }))
.padding(0.2);
svg.append("g")
.attr("transform", "translate(0," + height + ")")
.call(d3.axisBottom(x))
// Add Y axis
var y = d3.scaleLinear()
.domain([0, 20])
.range([ height, 0]);
svg.append("g")
.attr("class", "myYaxis")
.call(d3.axisLeft(y));
// A function that create / update the plot for a given variable:
function update(data) {
var u = svg.selectAll("rect")
.data(data)
u
.enter()
.append("rect")
.merge(u)
.transition()
.duration(1000)
.attr("x", function(d) { return x(d.group); })
.attr("y", function(d) { return y(d.value); })
.attr("width", x.bandwidth())
.attr("height", function(d) { return height - y(d.value); })
.attr("fill", "#69b3a2")
}
// Initialize the plot with the first dataset
update(data1)
</script>