93 lines
1.9 KiB
Markdown
93 lines
1.9 KiB
Markdown
---
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title: Use a Pre-Defined Scale to Place Elements
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---
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## Use a Pre-Defined Scale to Place Elements
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### Hint 1
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Use the `.attr()` function, which accepts 2 parameters.
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### Hint 2
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Use a callback function on the `.attr()` functions.
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### Hint 3
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The radius is set using the `r`attribute.
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### Solution
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Change the `svg.selectAll("circle")` and `svg.selectAll("text")` codeblocks to the following to complete the challenge, this has been done by incorporating all the hints from above:
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```js
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svg.selectAll("circle")
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.data(dataset)
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.enter()
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.append("circle")
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.attr("cx", (d) => xScale(d[0]))
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.attr("cy", (d) => yScale(d[1]))
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.attr("r", 5);
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svg.selectAll("text")
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.data(dataset)
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.enter()
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.append("text")
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.text((d) => (d[0] + ", " + d[1]))
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.attr("x", (d) => xScale(d[0] + 10))
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.attr("y", (d) => yScale(d[1]));
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```
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The full solution looks like:
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```html
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<body>
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<script>
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const dataset = [
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[ 34, 78 ],
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[ 109, 280 ],
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[ 310, 120 ],
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[ 79, 411 ],
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[ 420, 220 ],
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[ 233, 145 ],
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[ 333, 96 ],
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[ 222, 333 ],
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[ 78, 320 ],
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[ 21, 123 ]
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];
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const w = 500;
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const h = 500;
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const padding = 60;
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const xScale = d3.scaleLinear()
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.domain([0, d3.max(dataset, (d) => d[0])])
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.range([padding, w - padding]);
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const yScale = d3.scaleLinear()
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.domain([0, d3.max(dataset, (d) => d[1])])
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.range([h - padding, padding]);
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const svg = d3.select("body")
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.append("svg")
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.attr("width", w)
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.attr("height", h);
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svg.selectAll("circle")
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.data(dataset)
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.enter()
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.append("circle")
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.attr("cx", (d) => xScale(d[0]))
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.attr("cy", (d) => yScale(d[1]))
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.attr("r", 5);
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svg.selectAll("text")
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.data(dataset)
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.enter()
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.append("text")
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.text((d) => (d[0] + ", " + d[1]))
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.attr("x", (d) => xScale(d[0] + 10))
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.attr("y", (d) => yScale(d[1]));
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</script>
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</body>
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```
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