114 lines
2.9 KiB
Markdown
114 lines
2.9 KiB
Markdown
---
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id: 587d7fa8367417b2b2512bcd
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title: Create a Bar for Each Data Point in the Set
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challengeType: 6
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forumTopicId: 301482
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---
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## Description
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<section id='description'>
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The last challenge added only one rectangle to the <code>svg</code> element to represent a bar. Here, you'll combine what you've learned so far about <code>data()</code>, <code>enter()</code>, and SVG shapes to create and append a rectangle for each data point in <code>dataset</code>.
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A previous challenge showed the format for how to create and append a <code>div</code> for each item in <code>dataset</code>:
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```js
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d3.select("body").selectAll("div")
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.data(dataset)
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.enter()
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.append("div")
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```
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There are a few differences working with <code>rect</code> elements instead of <code>divs</code>. The <code>rects</code> must be appended to an <code>svg</code> element, not directly to the <code>body</code>. Also, you need to tell D3 where to place each <code>rect</code> within the <code>svg</code> area. The bar placement will be covered in the next challenge.
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</section>
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## Instructions
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<section id='instructions'>
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Use the <code>data()</code>, <code>enter()</code>, and <code>append()</code> methods to create and append a <code>rect</code> for each item in <code>dataset</code>. The bars should display all on top of each other; this will be fixed in the next challenge.
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</section>
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## Tests
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<section id='tests'>
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```yml
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tests:
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- text: Your document should have 9 <code>rect</code> elements.
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testString: assert($('rect').length == 9);
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- text: Your code should use the <code>data()</code> method.
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testString: assert(code.match(/\.data/g));
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- text: Your code should use the <code>enter()</code> method.
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testString: assert(code.match(/\.enter/g));
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- text: Your code should use the <code>append()</code> method.
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testString: assert(code.match(/\.append/g));
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```
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</section>
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## Challenge Seed
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<section id='challengeSeed'>
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<div id='html-seed'>
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```html
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<body>
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<script>
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const dataset = [12, 31, 22, 17, 25, 18, 29, 14, 9];
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const w = 500;
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const h = 100;
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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("rect")
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// Add your code below this line
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// Add your code above this line
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.attr("x", 0)
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.attr("y", 0)
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.attr("width", 25)
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.attr("height", 100);
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</script>
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</body>
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```
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</div>
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</section>
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## Solution
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<section id='solution'>
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```html
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<body>
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<script>
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const dataset = [12, 31, 22, 17, 25, 18, 29, 14, 9];
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const w = 500;
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const h = 100;
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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("rect")
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.data(dataset)
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.enter()
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.append("rect")
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.attr("x", 0)
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.attr("y", 0)
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.attr("width", 25)
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.attr("height", 100);
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</script>
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</body>
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```
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</section>
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