Filter data on multiple columns with checkboxes - D3
Question
I'm creating a scatterplot in D3 and I want to use checkboxes to filter the data by two categorical variables. Currently I can filter out data using the checkboxes, but if I re-check a box in one category it will bring back all the data for that category, regardless of what is checked/unchecked in the other category. I'd like to know how best to filter data according to multiple variables at once.
Here's a simplified version of my data and code:
Data ( test.csv ):
color,texture,length,width
blue,fluffy,4,1
yellow,fluffy,5,2
blue,grainy,3,1
yellow,grainy,4,2
blue,grainy,5,3
yellow,grainy,5,4
HTML:
<!DOCTYPE html>
<meta charset="utf-8">
<html lang="en">
<body>
<script src="http://d3js.org/d3.v3.min.js"></script>
<script type="text/javascript" src="test.js"></script>
<!-- Checkboxes -->
<div class="filter_options">
<input class="color_button" id="B" value="blue" type="checkbox"
checked="checked">Blue</input>
<input class="color_button" id="Y" value="yellow" type="checkbox"
checked="checked">Yellow</input>
</div>
<div class="filter_options">
<input class="texture_button" id="F" value="fluffy" type="checkbox"
checked="checked">Fluffy</input>
<input class="texture_button" id="G" value="grainy" type="checkbox"
checked="checked">Grainy</input>
</div>
</body>
</html>
Javascript ( test.js ; filtering happens at the bottom):
// Set width/height/margins
var margin = {top: 20, right: 20, bottom: 30, left: 50};
var w = 900 - margin.left - margin.right;
var h = 500 - margin.top - margin.bottom;
// Create SVG
var svg = d3.select("body").append("svg")
.attr("width", w + margin.left + margin.right)
.attr("height", h + margin.top + margin.bottom)
.append("g")
.attr("transform", "translate(" + margin.left + "," + margin.top + ")");
// x and y scales
var x = d3.scale.linear()
.domain([0, 10])
.range([0, w]);
var y = d3.scale.linear()
.domain([0, 10])
.range([h, 0]);
// x axis
var xAxis = d3.svg.axis()
.ticks(6)
.scale(x);
// y axis
var yAxis = d3.svg.axis()
.ticks(7)
.scale(y)
.orient("left");
// Colors for points
var col = d3.scale.ordinal()
.domain(["blue", "yellow"])
.range(["#3b80e8", "#ecea5f"]);
// Add x axis ("Length")
svg.append("g")
.attr("class", "axis")
.attr("transform", "translate(0," + h + ")")
.call(xAxis)
.append("text")
.attr("x", w)
.attr("y", -6)
.style("text-anchor", "end")
.text("Length");
// Add y axis ("Width")
svg.append("g")
.attr("class", "axis")
.call(yAxis)
.append("text")
.attr("transform", "rotate(-90)")
.attr("y", 6)
.attr("dy", ".71em")
.style("text-anchor", "end")
.text("Width");
// Data
var dat;
d3.csv("test.csv", function(data) {
data.forEach(function(d) {
d.length = +d.length;
d.width = +d.width;
});
// Scatterplot
svg.selectAll(".dot")
.data(data)
.enter()
.append("circle")
.attr("class", "dot")
.attr("cx", function(d) {return x(d.length); })
.attr("cy", function(d) {return y(d.width); })
.attr("r", 7)
.style("fill", function(d) { return col(d.color); });
// Filter data by color
d3.selectAll(".color_button").on("change", function() {
var selected = this.value,
display = this.checked ? "inline" : "none";
svg.selectAll(".dot")
.filter(function(d) { return selected == d.color; })
.attr("display", display);
});
// Filter data by texture
d3.selectAll(".texture_button").on("change", function() {
var selected = this.value,
display = this.checked ? "inline" : "none";
svg.selectAll(".dot")
.filter(function(d) { return selected == d.texture; })
.attr("display", display);
});
});
In the resulting graph, if I uncheck "blue", all the blue points disappear. If I uncheck "fluffy", one more point disappears. If I then re-check "fluffy", I get back the one yellow fluffy point as well as the one blue fluffy point. I think I can see why this is happening with my code as I've written it: since when I re-check "fluffy" I'm not changing changing the state of the color checkboxes, my data isn't getting filtered according to color. I'm brand new to D3 and Javascript, so I don't know how to do better accomplish filtering on multiple columns at the same time.
1 answers
solution1
1 ACCPTED 2016-02-14 23:35:45
Here's one way to do it. Replace the two filtering code fragments with this:
// a function that will be responsible for updating the visibility of the dots
function update() {
// colors will be the array of active colors, i.e. if only the yellow checkbox
// is checked, it will be ['yellow']
var colors = d3.selectAll('.color_button')[0]
.filter(function(e) { return e.checked; })
.map(function(e) { return e.value; });
// same thing for the textures
var textures = d3.selectAll('.texture_button')[0]
.filter(function(e) { return e.checked; })
.map(function(e) { return e.value; });
// a helper function that will return the correct display value
// it will be called for every dot
function display(d) {
// we check if the current dot's color and texture are present in the
// colors and textures arrays.
if (colors.indexOf(d.color) !== -1 && textures.indexOf(d.texture) !== -1) {
return 'inline';
} else {
return 'none';
}
}
// we change the display attribute of every dot using the display function just defined
svg.selectAll('.dot').attr('display', display);
}
// we add a simple handler to all the checkboxes: every time one changes,
// just call update
d3.selectAll(".filter_options input").on("change", update);
The technical post webpages of this site follow the CC BY-SA 4.0 protocol. If you need to reprint, please indicate the site URL or the original address.Any question please contact:yoyou2525@163.com.