#DataScience #DataViz #WebApplications
Published
Edited
Jul 19, 2021
2 stars
md`# How to Build a Dynamic Bar Chart through sqlite3
## Load sqlite3 file`
db = FileAttachment("food_db").sqlite()
db.describe()
db.describe('food_table')
n = db.query(`SELECT count(*) as N from food_table`)
n[0]
md `## Define the query
List all possible groups and build the dropdown menu`
groups = db.query('SELECT DISTINCT(`GROUP`) from food_table')
viewof term = Inputs.select(groups.map(d => d.GROUP), {value: "Vegetables", label: "Group"})
data = db.query('SELECT count(*) AS value, `SUB GROUP` AS name FROM food_table WHERE `GROUP` LIKE $1 GROUP BY name ORDER BY value DESC', [`%${term}%`])
Inputs.table(data)
md `## Plot Bar Chart`
chart = {
const svg = d3.create("svg")
.attr("viewBox", [0, 0, width, height]);
svg.append("g")
.attr("fill", color)
.selectAll("rect")
.data(data)
.join("rect")
.attr("x", (d, i) => x(i))
.attr("y", d => y(d.value))
.attr("height", d => y(0) - y(d.value))
.attr("width", x.bandwidth());
svg.append("g")
.call(xAxis);
svg.append("g")
.call(yAxis);
return svg.node();
}
x = d3.scaleBand()
.domain(d3.range(data.length))
.range([margin.left, width - margin.right])
.padding(0.1)
y = d3.scaleLinear()
.domain([0, d3.max(data, d => d.value)]).nice()
.range([height - margin.bottom, margin.top])
xAxis = g => g
.attr("transform", `translate(0,${height - margin.bottom})`)
.call(d3.axisBottom(x).tickFormat(i => data[i].name).tickSizeOuter(0))
yAxis = g => g
.attr("transform", `translate(${margin.left},0)`)
.call(d3.axisLeft(y).ticks(null, data.format))
.call(g => g.select(".domain").remove())
.call(g => g.append("text")
.attr("x", -margin.left)
.attr("y", 10)
.attr("fill", "currentColor")
.attr("text-anchor", "start")
.text(data.y))
color = "steelblue"
height = 300
margin = ({top: 30, right: 0, bottom: 30, left: 40})
Purpose-built for displays of data
Observable is your go-to platform for exploring data and creating expressive data visualizations. Use reactive JavaScript notebooks for prototyping and a collaborative canvas for visual data exploration and dashboard creation.
