112 lines
		
	
	
		
			3.9 KiB
		
	
	
	
		
			Markdown
		
	
	
	
	
	
			
		
		
	
	
			112 lines
		
	
	
		
			3.9 KiB
		
	
	
	
		
			Markdown
		
	
	
	
	
	
---
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id: 587d7faa367417b2b2512bd6
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title: Add a Tooltip to a D3 Element
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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: 将工具提示添加到D3元素
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---
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## Description
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<section id="description">当用户将鼠标悬停在该项目上时,工具提示会显示有关页面上项目的更多信息。有几种方法可以向可视化添加工具提示,此挑战使用SVG <code>title</code>元素。 <code>title</code>对与<code>text()</code>方法一起动态地向条形图添加数据。 </section>
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## Instructions
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<section id="instructions">在每个<code>rect</code>节点下附加<code>title</code>元素。然后使用回调函数调用<code>text()</code>方法,以便文本显示数据值。 </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: 您的代码应该有9个<code>title</code>元素。
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    testString: 'assert($("title").length == 9, "Your code should have 9 <code>title</code> elements.");'
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  - text: 第一个<code>title</code>元素的工具提示文本应为12。
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    testString: 'assert($("title").eq(0).text() == "12", "The first <code>title</code> element should have tooltip text of 12.");'
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  - text: 第二个<code>title</code>元素的工具提示文本应为31。
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    testString: 'assert($("title").eq(1).text() == "31", "The second <code>title</code> element should have tooltip text of 31.");'
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  - text: 第三个<code>title</code>元素的工具提示文本应为22。
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    testString: 'assert($("title").eq(2).text() == "22", "The third <code>title</code> element should have tooltip text of 22.");'
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  - text: 第四个<code>title</code>元素的工具提示文本应为17。
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    testString: 'assert($("title").eq(3).text() == "17", "The fourth <code>title</code> element should have tooltip text of 17.");'
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  - text: 第五个<code>title</code>元素的工具提示文本应为25。
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    testString: 'assert($("title").eq(4).text() == "25", "The fifth <code>title</code> element should have tooltip text of 25.");'
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  - text: 第六个<code>title</code>元素的工具提示文本应为18。
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    testString: 'assert($("title").eq(5).text() == "18", "The sixth <code>title</code> element should have tooltip text of 18.");'
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  - text: 第七个<code>title</code>元素的工具提示文本应为29。
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    testString: 'assert($("title").eq(6).text() == "29", "The seventh <code>title</code> element should have tooltip text of 29.");'
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  - text: 第八个<code>title</code>元素的工具提示文本应为14。
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    testString: 'assert($("title").eq(7).text() == "14", "The eighth <code>title</code> element should have tooltip text of 14.");'
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  - text: 第九个<code>title</code>元素的工具提示文本应为9。
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    testString: 'assert($("title").eq(8).text() == "9", "The ninth <code>title</code> element should have tooltip text of 9.");'
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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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<style>
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  .bar:hover {
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    fill: brown;
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  }
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</style>
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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) => d * 3)
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       .attr("fill", "navy")
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       .attr("class", "bar")
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       // Add your code below this line
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       // Add your code above this line
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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)
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       .attr("x", (d, i) => i * 30)
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       .attr("y", (d, i) => h - (d * 3 + 3))
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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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