79d9012432
* fix(curriculum): tests quotes * fix(curriculum): fill seed-teardown * fix(curriculum): fix tests and remove unneeded seed-teardown
111 lines
7.4 KiB
Markdown
111 lines
7.4 KiB
Markdown
---
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id: 587d7fab367417b2b2512bd8
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title: Add Attributes to the Circle Elements
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required:
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- src: 'https://cdnjs.cloudflare.com/ajax/libs/d3/4.3.0/d3.min.js'
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challengeType: 6
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---
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## Description
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<section id='description'>
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The last challenge created the <code>circle</code> elements for each point in the <code>dataset</code>, and appended them to the SVG canvas. But D3 needs more information about the position and size of each <code>circle</code> to display them correctly.
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A <code>circle</code> in SVG has three main attributes. The <code>cx</code> and <code>cy</code> attributes are the coordinates. They tell D3 where to position the <em>center</em> of the shape on the SVG canvas. The radius (<code>r</code> attribute) gives the size of the <code>circle</code>.
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Just like the <code>rect</code> <code>y</code> coordinate, the <code>cy</code> attribute for a <code>circle</code> is measured from the top of the SVG canvas, not from the bottom.
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All three attributes can use a callback function to set their values dynamically. Remember that all methods chained after <code>data(dataset)</code> run once per item in <code>dataset</code>. The <code>d</code> parameter in the callback function refers to the current item in <code>dataset</code>, which is an array for each point. You use bracket notation, like <code>d[0]</code>, to access the values in that array.
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</section>
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## Instructions
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<section id='instructions'>
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Add <code>cx</code>, <code>cy</code>, and <code>r</code> attributes to the <code>circle</code> elements. The <code>cx</code> value should be the first number in the array for each item in <code>dataset</code>. The <code>cy</code> value should be based off the second number in the array, but make sure to show the chart right-side-up and not inverted. The <code>r</code> value should be 5 for all circles.
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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 code should have 10 <code>circle</code> elements.
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testString: assert($('circle').length == 10, 'Your code should have 10 <code>circle</code> elements.');
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- text: The first <code>circle</code> element should have a <code>cx</code> value of 34, a <code>cy</code> value of 422, and an <code>r</code> value of 5.
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testString: assert($('circle').eq(0).attr('cx') == '34' && $('circle').eq(0).attr('cy') == '422' && $('circle').eq(0).attr('r') == '5', 'The first <code>circle</code> element should have a <code>cx</code> value of 34, a <code>cy</code> value of 422, and an <code>r</code> value of 5.');
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- text: The second <code>circle</code> element should have a <code>cx</code> value of 109, a <code>cy</code> value of 220, and an <code>r</code> value of 5.
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testString: assert($('circle').eq(1).attr('cx') == '109' && $('circle').eq(1).attr('cy') == '220' && $('circle').eq(1).attr('r') == '5', 'The second <code>circle</code> element should have a <code>cx</code> value of 109, a <code>cy</code> value of 220, and an <code>r</code> value of 5.');
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- text: The third <code>circle</code> element should have a <code>cx</code> value of 310, a <code>cy</code> value of 380, and an <code>r</code> value of 5.
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testString: assert($('circle').eq(2).attr('cx') == '310' && $('circle').eq(2).attr('cy') == '380' && $('circle').eq(2).attr('r') == '5', 'The third <code>circle</code> element should have a <code>cx</code> value of 310, a <code>cy</code> value of 380, and an <code>r</code> value of 5.');
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- text: The fourth <code>circle</code> element should have a <code>cx</code> value of 79, a <code>cy</code> value of 89, and an <code>r</code> value of 5.
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testString: assert($('circle').eq(3).attr('cx') == '79' && $('circle').eq(3).attr('cy') == '89' && $('circle').eq(3).attr('r') == '5', 'The fourth <code>circle</code> element should have a <code>cx</code> value of 79, a <code>cy</code> value of 89, and an <code>r</code> value of 5.');
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- text: The fifth <code>circle</code> element should have a <code>cx</code> value of 420, a <code>cy</code> value of 280, and an <code>r</code> value of 5.
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testString: assert($('circle').eq(4).attr('cx') == '420' && $('circle').eq(4).attr('cy') == '280' && $('circle').eq(4).attr('r') == '5', 'The fifth <code>circle</code> element should have a <code>cx</code> value of 420, a <code>cy</code> value of 280, and an <code>r</code> value of 5.');
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- text: The sixth <code>circle</code> element should have a <code>cx</code> value of 233, a <code>cy</code> value of 355, and an <code>r</code> value of 5.
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testString: assert($('circle').eq(5).attr('cx') == '233' && $('circle').eq(5).attr('cy') == '355' && $('circle').eq(5).attr('r') == '5', 'The sixth <code>circle</code> element should have a <code>cx</code> value of 233, a <code>cy</code> value of 355, and an <code>r</code> value of 5.');
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- text: The seventh <code>circle</code> element should have a <code>cx</code> value of 333, a <code>cy</code> value of 404, and an <code>r</code> value of 5.
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testString: assert($('circle').eq(6).attr('cx') == '333' && $('circle').eq(6).attr('cy') == '404' && $('circle').eq(6).attr('r') == '5', 'The seventh <code>circle</code> element should have a <code>cx</code> value of 333, a <code>cy</code> value of 404, and an <code>r</code> value of 5.');
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- text: The eighth <code>circle</code> element should have a <code>cx</code> value of 222, a <code>cy</code> value of 167, and an <code>r</code> value of 5.
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testString: assert($('circle').eq(7).attr('cx') == '222' && $('circle').eq(7).attr('cy') == '167' && $('circle').eq(7).attr('r') == '5', 'The eighth <code>circle</code> element should have a <code>cx</code> value of 222, a <code>cy</code> value of 167, and an <code>r</code> value of 5.');
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- text: The ninth <code>circle</code> element should have a <code>cx</code> value of 78, a <code>cy</code> value of 180, and an <code>r</code> value of 5.
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testString: assert($('circle').eq(8).attr('cx') == '78' && $('circle').eq(8).attr('cy') == '180' && $('circle').eq(8).attr('r') == '5', 'The ninth <code>circle</code> element should have a <code>cx</code> value of 78, a <code>cy</code> value of 180, and an <code>r</code> value of 5.');
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- text: The tenth <code>circle</code> element should have a <code>cx</code> value of 21, a <code>cy</code> value of 377, and an <code>r</code> value of 5.
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testString: assert($('circle').eq(9).attr('cx') == '21' && $('circle').eq(9).attr('cy') == '377' && $('circle').eq(9).attr('r') == '5', 'The tenth <code>circle</code> element should have a <code>cx</code> value of 21, a <code>cy</code> value of 377, and an <code>r</code> value of 5.');
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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 = [
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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 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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// Add your code below this line
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// Add your code above this line
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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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```js
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// solution required
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```
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</section>
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