29:null 2a:["$","title",null,{"children":"Introduction to D3 Course: Lesson 5 | 🪦 dv develop 2026 spring | Observable"}] 2f:T553,{ const width = 900; const height = 300; const marginTop = 25; const marginRight = 20; const marginBottom = 35; const marginLeft = 60; const x = d3 .scaleBand() .domain(Array.from(new Set(populationData.map((d) => d.name)))) .range([0, width]); const y = d3 .scaleLinear() .domain([0, d3.max(stackLayout, (d) => d3.max(d, (d) => d[1]))]) .nice() .range([height, 0]); const color = d3 .scaleOrdinal() .domain(keys) .range(d3.schemeSpectral[keys.length]); const svg = d3 .create("svg") .attr("width", width + marginLeft + marginRight) .attr("height", height + marginTop + marginBottom); const g = svg .append("g") .attr("transform", `translate(${marginLeft}, ${marginTop})`); // Append a group for each series, and a rect for each element in the series. g.append("g") .selectAll(".bucket") .data(stackLayout) .join("g") .attr("class", "bucket") .attr("fill", (_, i) => color(keys[i])) .selectAll("rect") .data((d) => d) .join("rect") .attr("x", (d) => x(d.data.name)) .attr("y", (d) => y(d[1])) .attr("height", (d) => y(d[0]) - y(d[1])) .attr("width", x.bandwidth()); g.append("g") .attr("transform", `translate(0,${height})`) .call(d3.axisBottom(x)); g.append("g").call(d3.axisLeft(y)); return svg.node(); }30:T48c,{ const width = 200; const height = 200; const margin = { top: 20, bottom: 20, left: 20, right: 20 }; const svg = d3 .create("svg") .attr("width", width + margin.left + margin.right) .attr("height", height + margin.top + margin.bottom); const g = svg .append("g") .attr("transform", `translate(${margin.left}, ${margin.top})`); const rectangle = g .append("rect") .attr("width", width) .attr("height", height) .style("fill", "#ddd") .style("stroke", "#000") .on("mouseenter", (event) => { rectangle.style("fill", "yellow"); }) .on("mouseleave", (event) => { rectangle.style("fill", "blue"); }) .on("click", (events) => { rectangle .transition() .duration(2000) .attr("width", 0) .attr("height", 0) .attr("x", width / 2) .attr("y", height / 2); }); const circle = g .append("circle") .style("pointer-events", "none") .attr("r", 5); svg.on("mousemove", (event) => { console.log(event); circle.attr("cx", event.layerX - 20); circle.attr("cy", event.layerY - 20); }); return svg.node(); }31:Tadf,{ const width = 600; const height = 400; const margin = { top: 30, bottom: 20, left: 50, right: 50 }; const div = htl.html`

`; const categories = d3.groups(iris, (d) => d.species); const buttons = d3 .select(div) .selectAll("button") .data(categories) .join("button"); buttons.text((d) => d[0]); const svg = d3 .select(div) .append("div") .append("svg") .attr("width", width + margin.left + margin.right) .attr("height", height + margin.top + margin.bottom); const g = svg .append("g") .attr("transform", `translate(${margin.left}, ${margin.top})`); g.append("rect") .attr("width", width) .attr("height", height) .style("fill", "#eee"); const text = svg .append("text") .style("font", "12px sans-serif") .attr("y", 15) .text("Click on a circle to read the data!"); const x = d3 .scaleLinear() .domain(d3.extent(iris, (d) => d["sepalLength"])) .nice() .range([0, width]); const y = d3 .scaleLinear() .domain(d3.extent(iris, (d) => d["sepalWidth"])) .nice() .range([height, 0]); const color = d3 .scaleOrdinal() .domain(categories.map((d) => d[0])) .range(d3.schemeDark2); const yAxis = g.append("g").call(d3.axisLeft(y).tickSize(-width)); const xAxis = g .append("g") .attr("transform", `translate(0, ${height})`) .call(d3.axisBottom(x).tickSize(-height)); yAxis.selectAll("line").style("stroke", "#fff"); xAxis.selectAll("line").style("stroke", "#fff"); const circles = g .selectAll("circle") .data(iris.filter((d) => d.species == "setosa")) .join("circle") .attr("r", 4) .style("stroke", "#000") .attr("cx", (d) => x(d.sepalLength)) .attr("cy", (d) => y(d.sepalWidth)) .style("fill", (d) => color(d.species)) .style("cursor", "pointer") .on("click", (event, d) => { text.text(JSON.stringify(d)); }); buttons.on("click", (event, d) => { g.selectAll("circle") .data(d[1], (d) => d) .join( (enter) => enter.append("circle") .attr("r", 4) .style("stroke", "#000") .attr("cx", (d) => x(d.sepalLength)) .attr("cy", (d) => y(d.sepalWidth)) .style("fill", (d) => color(d.species)) .style("cursor", "pointer") // ---> ADDED/VERIFIED CLICK LISTENER HERE <--- .on("click", (mouseEvent, data) => { text.text(JSON.stringify(data)); }), (update) => update .attr("cx", (d) => x(d.sepalLength)) .attr("cy", (d) => y(d.sepalWidth)) .style("fill", (d) => color(d.species)), (exit) => exit .attr("fill", "red") .call((exit) => exit.transition().duration(1000).attr("r", 0).remove()) ); }); return div; }32:T435,testYourKnowledge([ { title: 'Data Structures', backText: [`Converting a tabular data structure to a hierarchical data structures is about creating a structure better suited for your visualization, not about creating efficiency.`, `A hierarchical data structure can introduct complexity which may not be best for all situations.`], question: "Hierarchical data structres are more efficient that tabular data structures", answer: false }, { title: 'Thinking in D3', backText: ['Thinking in D3 ', ''], question: 'Thinking in D3 means thinking more criticically about the components that go into a visualization', answer: true }, { title: 'Interaction', backText: [`While event listeners are built-in method with D3 selections, its interaction does not come out of the box. You need to specify the event and interaction that results.`, `D3 uses web standards for event listeners, so you can use any web-standard event in your D3 visualization.`], question: `Interaction with D3 comes out of the box.`, answer: false }, ], 300, 300)33:[{"id":"a2810faa56f2edca2606a76bffb24e6c150fbf4b70512f35fd794a3c52144d51dbc70db3c4d3158c935f13fba1f66ca3425cc65f7e8bea9c70a493b532fabbdc","href":"https://static.observableusercontent.com/files/a2810faa56f2edca2606a76bffb24e6c150fbf4b70512f35fd794a3c52144d51dbc70db3c4d3158c935f13fba1f66ca3425cc65f7e8bea9c70a493b532fabbdc","name":"iris.csv","type":"text/csv","lastModified":1779139497421.018,"size":3712},{"id":"3ea96de39eb40936da1c5e7bf932e124861c50b9e45569cb17e694e9b9ed462c79684b2ede7266422ee880930d43408010a4741695709c094f9f6827c62534db","href":"https://static.observableusercontent.com/files/3ea96de39eb40936da1c5e7bf932e124861c50b9e45569cb17e694e9b9ed462c79684b2ede7266422ee880930d43408010a4741695709c094f9f6827c62534db","name":"us-population-state-age.csv","type":"text/csv","lastModified":1779139497421.018,"size":3516}] 2d:{"id":"5aa79c76f50bbbac","slug":null,"title":"Introduction to D3 Course: Lesson 5","thumbnail":"0e4dfd50ab646cd9965cea7d5d3432a9e733017fa69230c61cacd5f055fd76bc","access_level":"public","create_time":"$D2026-05-18T21:24:57.421Z","update_time":"$D2026-05-18T21:27:39.022Z","view_time":null,"first_public_time":"$D2026-05-18T21:44:04.975Z","fork":{"id":"adf87cc9bddfd34b","slug":"introduction-to-d3-course-lesson-5","title":"Introduction to D3 Course: Lesson 5","owner":{"id":"f35c755083683fe5","login":"observablehq","name":"Observable"}},"stars":0,"starred":false,"owner":{"type":"team","id":"9409263e557ef66a","login":"dv-develop-2026s","name":"🪦 dv develop 2026 spring","avatar_url":"https://avatars-next.observableusercontent.com/83690145de7111a45dea712eea168cd084ea0cae2d94bdcfa6f9f12e6402cad6","tier":"pro_2024"},"version":160,"publish_version":null,"role":null,"authored":false,"authors":[{"type":"individual","id":"aa99df3a6fb6674d","login":"sisi2","name":"Sisi","avatar_url":"https://avatars-next.observableusercontent.com/d31c20cac024f6372a84a376a83cae25107276e3c424f915425b5e7f65ee4623","tier":null}],"members":[{"type":"team","id":"9409263e557ef66a","login":"dv-develop-2026s","name":"🪦 dv develop 2026 spring","avatar_url":"https://avatars-next.observableusercontent.com/83690145de7111a45dea712eea168cd084ea0cae2d94bdcfa6f9f12e6402cad6","tier":"pro_2024","role":"editor"},{"type":"individual","id":"aa99df3a6fb6674d","login":"sisi2","name":"Sisi","avatar_url":"https://avatars-next.observableusercontent.com/d31c20cac024f6372a84a376a83cae25107276e3c424f915425b5e7f65ee4623","tier":null,"role":"editor"}],"comments":[],"custom_thumbnail":false,"trashed":false,"subscribed":null,"forks":0,"collection":null,"type":"notebook","body":{"title":"Introduction to D3 Course: Lesson 5","cells":[{"id":5,"value":"# Introduction to D3 Course: Lesson 5\n## Thinking in D3\n\n[Session 5 slide deck](https://docs.google.com/presentation/d/1obvcXsmiuH-xOQh3v3ItjSmDRjNU0u4bcEaK0wCNr8U/edit?usp=sharing)","pinned":false,"hidden":false,"mode":"md","author":"$undefined","summary":"$undefined","output":"","database":"$undefined"},{"id":6,"value":"---\n## Activity 1\n
","pinned":false,"hidden":false,"mode":"md","author":"$undefined","summary":"$undefined","output":"","database":"$undefined"},{"id":42,"value":"### Hierarchical Data with Stack Layout\n- Create a new stack layout function, using the population dataset by state, making the keys the various age buckets.\n - Compare datasets to see what changed. Is the data set the same structure? Is it smaller or larger?\n- Create a stacked bar chart with the x-axis being each state, and the y axis being the total population, bars colored by their key.\n - Use a band scale to handle for the bar widths\n - Nest a d3.max within the d3.max to get the max y scale value.\n - Use a nested structure to our elements, so that there is a group for each key.","pinned":false,"hidden":false,"mode":"md","author":"$undefined","summary":"$undefined","output":"","database":"$undefined"},{"id":153,"value":"populationData","pinned":true,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined","output":"","database":"$undefined"},{"id":43,"value":"populationData","pinned":true,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined","output":"$undefined","database":"$undefined"},{"id":44,"value":"keys = [\"<10\", \"10-19\", \"20-29\", \"30-39\", \"40-49\", \"50-59\", \"60-69\", \"70-79\", \"≥80\"]","pinned":true,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined","output":"$undefined","database":"$undefined"},{"id":45,"value":"stackLayout = d3.stack().keys(keys).offset(d3.stackOffsetExpand)(populationData)","pinned":true,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined","output":"$undefined","database":"$undefined"},{"id":46,"value":"$2f","pinned":true,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined","output":"$undefined","database":"$undefined"},{"id":25,"value":"---\n## Activity 2\n
","pinned":false,"hidden":false,"mode":"md","author":"$undefined","summary":"$undefined","output":"","database":"$undefined"},{"id":117,"value":"### Interaction with Event Listeners\n- Make the rectangle turn yellow when you enter the rectangle.\n- Make the rectangle turn blue when you leave the rectangle.\n- Make the rectangle shrink into nothingness when you click on the rectangle.","pinned":false,"hidden":false,"mode":"md","author":"$undefined","summary":"$undefined","output":"","database":"$undefined"},{"id":111,"value":"$30","pinned":true,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined","output":"$undefined","database":"$undefined"},{"id":26,"value":"---\n## Activity 3\n
","pinned":false,"hidden":false,"mode":"md","author":"$undefined","summary":"$undefined","output":"","database":"$undefined"},{"id":145,"value":"### Interaction with Event Listeners\n- Add an click event listener to the circles so you can read the data bound to each element.","pinned":false,"hidden":false,"mode":"md","author":"$undefined","summary":"$undefined","output":"","database":"$undefined"},{"id":123,"value":"$31","pinned":true,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined","output":"$undefined","database":"$undefined"},{"id":7,"value":"---\n## Wrap Up\nTest your knowledge from session one with these short questions.","pinned":false,"hidden":false,"mode":"md","author":"$undefined","summary":"$undefined","output":"","database":"$undefined"},{"id":8,"value":"$32","pinned":false,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined","output":"$undefined","database":"$undefined"},{"id":9,"value":"

","pinned":false,"hidden":false,"mode":"md","author":"$undefined","summary":"$undefined","output":"","database":"$undefined"},{"id":10,"value":"

","pinned":false,"hidden":false,"mode":"md","author":"$undefined","summary":"$undefined","output":"","database":"$undefined"},{"id":11,"value":"

","pinned":false,"hidden":false,"mode":"md","author":"$undefined","summary":"$undefined","output":"","database":"$undefined"},{"id":12,"value":"

","pinned":false,"hidden":false,"mode":"md","author":"$undefined","summary":"$undefined","output":"","database":"$undefined"},{"id":13,"value":"---\n## Appendix","pinned":false,"hidden":false,"mode":"md","author":"$undefined","summary":"$undefined","output":"","database":"$undefined"},{"id":14,"value":"import {note} from \"@observablehq/callout-boxes\"","pinned":false,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined","output":"$undefined","database":"$undefined"},{"id":15,"value":"import { showMe } from \"@observablehq/show-me\"","pinned":false,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined","output":"$undefined","database":"$undefined"},{"id":16,"value":"import {testYourKnowledge} from \"@observablehq/test-your-knowledge-cards\"","pinned":false,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined","output":"$undefined","database":"$undefined"},{"id":17,"value":"color = d3.schemeBlues[7]","pinned":false,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined","output":"$undefined","database":"$undefined"},{"id":76,"value":"populationData = await FileAttachment(\"us-population-state-age.csv\").csv({typed: true});","pinned":false,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined","output":"$undefined","database":"$undefined"},{"id":125,"value":"iris = await FileAttachment(\"iris.csv\").csv({typed: \"auto\"})","pinned":true,"hidden":true,"mode":"ojs","author":"$undefined","summary":"$undefined","output":"iris","database":"$undefined"}],"files":"$W33","stdlib":"1","titling":"auto"}} 2e:"$2d:body"