100 lines
4.6 KiB
Markdown
100 lines
4.6 KiB
Markdown
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---
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id: 587d7faa367417b2b2512bd2
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title: Add Labels to D3 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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videoUrl: ''
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localeTitle: 将标签添加到D3元素
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---
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## Description
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<section id="description"> D3允许您使用SVG <code>text</code>元素标记图形元素，例如条形图。与<code>rect</code>元素一样， <code>text</code>元素需要具有<code>x</code>和<code>y</code>属性，以将其放在SVG画布上。它还需要访问数据以显示这些值。 D3让您可以高度控制标杆的标注方式。 </section>
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## Instructions
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<section id="instructions">编辑器中的代码已将数据绑定到每个新<code>text</code>元素。首先，将<code>text</code>节点附加到<code>svg</code> 。接下来，添加<code>x</code>和<code>y</code>坐标的属性。应该以与<code>rect</code>相同的方式计算它们，除了<code>text</code>的<code>y</code>值应该使标签比条形高3个单位。最后，使用D3 <code>text()</code>方法将标签设置为等于数据点值。 <strong>注意</strong> <br>对于标签比坐吧较高，决定是否<code>y</code>为值<code>text</code>应比少3个或大或3 <code>y</code>了吧价值。 </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: 第一个<code>text</code>元素的标签应为12， <code>y</code>值应为61。
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testString: 'assert($("text").eq(0).text() == "12" && $("text").eq(0).attr("y") == "61", "The first <code>text</code> element should have a label of 12 and a <code>y</code> value of 61.");'
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- text: 第二个<code>text</code>元素的标签应为31， <code>y</code>值应为4。
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testString: 'assert($("text").eq(1).text() == "31" && $("text").eq(1).attr("y") == "4", "The second <code>text</code> element should have a label of 31 and a <code>y</code> value of 4.");'
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- text: 第三个<code>text</code>元素的标签应为22， <code>y</code>值应为31。
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testString: 'assert($("text").eq(2).text() == "22" && $("text").eq(2).attr("y") == "31", "The third <code>text</code> element should have a label of 22 and a <code>y</code> value of 31.");'
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- text: 第四个<code>text</code>元素的标签应为17， <code>y</code>值应为46。
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testString: 'assert($("text").eq(3).text() == "17" && $("text").eq(3).attr("y") == "46", "The fourth <code>text</code> element should have a label of 17 and a <code>y</code> value of 46.");'
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- text: 第五个<code>text</code>元素的标签应为25， <code>y</code>值应为22。
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testString: 'assert($("text").eq(4).text() == "25" && $("text").eq(4).attr("y") == "22", "The fifth <code>text</code> element should have a label of 25 and a <code>y</code> value of 22.");'
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- text: 第六个<code>text</code>元素的标签应为18， <code>y</code>值应为43。
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testString: 'assert($("text").eq(5).text() == "18" && $("text").eq(5).attr("y") == "43", "The sixth <code>text</code> element should have a label of 18 and a <code>y</code> value of 43.");'
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- text: 第七个<code>text</code>元素的标签应为29， <code>y</code>值应为10。
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testString: 'assert($("text").eq(6).text() == "29" && $("text").eq(6).attr("y") == "10", "The seventh <code>text</code> element should have a label of 29 and a <code>y</code> value of 10.");'
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- text: 第八个<code>text</code>元素的标签应为14， <code>y</code>值应为55。
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testString: 'assert($("text").eq(7).text() == "14" && $("text").eq(7).attr("y") == "55", "The eighth <code>text</code> element should have a label of 14 and a <code>y</code> value of 55.");'
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- text: 第九个<code>text</code>元素的标签应为9， <code>y</code>值应为70。
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testString: 'assert($("text").eq(8).text() == "9" && $("text").eq(8).attr("y") == "70", "The ninth <code>text</code> element should have a label of 9 and a <code>y</code> value of 70.");'
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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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.data(dataset)
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.enter()
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.append("rect")
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.attr("x", (d, i) => i * 30)
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.attr("y", (d, i) => h - 3 * d)
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.attr("width", 25)
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.attr("height", (d, i) => 3 * d)
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.attr("fill", "navy");
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svg.selectAll("text")
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.data(dataset)
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.enter()
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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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