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											2018-10-10 18:03:03 -04:00
										 |  |  |  | --- | 
					
						
							|  |  |  |  | id: 587d7fab367417b2b2512bd9 | 
					
						
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										 |  |  |  | title: 向散点图的 Circles 添加标签 | 
					
						
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											2018-10-10 18:03:03 -04:00
										 |  |  |  | challengeType: 6 | 
					
						
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										 |  |  |  | forumTopicId: 301477 | 
					
						
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										 |  |  |  | dashedName: add-labels-to-scatter-plot-circles | 
					
						
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											2018-10-10 18:03:03 -04:00
										 |  |  |  | --- | 
					
						
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										 |  |  |  | # --description--
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										 |  |  |  | 你可以为散点图中的点添加文本来创建标签。 | 
					
						
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										 |  |  |  | 目标是显示 `dataset` 中每个对象的第一个(`x`)和第二个(`y`)字段中通过逗号分隔的值。 | 
					
						
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										 |  |  |  | `text` 节点需要 `x` 和 `y` 属性来指定放置在 SVG 画布中的位置。 在这个挑战中,`y` 值(决定高度)可以用和 `circle` 的 `cy` 属性相同的值, `x` 值可以比 `circle` 的 `cx` 值稍微大一些,这样标签才可见, 并且被放置在散点的右边。 | 
					
						
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							|  |  |  |  | # --instructions--
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										 |  |  |  | 使用 `text` 元素标记散点图上的每个点。 标签的文本应该是用逗号和空格分隔的两个值。 例如,第一个点的标签是 `34, 78`。 设置 `x` 属性,使其比 `circle` 上的 `cx` 属性的值多 `5` 个单位。 设置 `y` 属性的方式与 `circle` 上的 `cy` 值相同。 | 
					
						
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							|  |  |  |  | # --hints--
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										 |  |  |  | 应该有 10 个 `text` 元素。 | 
					
						
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							|  |  |  |  | ```js | 
					
						
							|  |  |  |  | assert($('text').length == 10); | 
					
						
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										 |  |  |  | ``` | 
					
						
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										 |  |  |  | 第一个标签的文本应为 `34, 78`, `x` 值应为 `39`,`y` 应为 `422`。 | 
					
						
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							|  |  |  |  | ```js | 
					
						
							|  |  |  |  | assert( | 
					
						
							|  |  |  |  |   $('text').eq(0).text() == '34, 78' && | 
					
						
							|  |  |  |  |     $('text').eq(0).attr('x') == '39' && | 
					
						
							|  |  |  |  |     $('text').eq(0).attr('y') == '422' | 
					
						
							|  |  |  |  | ); | 
					
						
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										 |  |  |  | ``` | 
					
						
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										 |  |  |  | 第二个标签的文本应为 `109, 280`,`x` 值应为`114`,`y` 值应为 `220`。 | 
					
						
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										 |  |  |  | ```js | 
					
						
							|  |  |  |  | assert( | 
					
						
							|  |  |  |  |   $('text').eq(1).text() == '109, 280' && | 
					
						
							|  |  |  |  |     $('text').eq(1).attr('x') == '114' && | 
					
						
							|  |  |  |  |     $('text').eq(1).attr('y') == '220' | 
					
						
							|  |  |  |  | ); | 
					
						
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										 |  |  |  | ``` | 
					
						
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											2020-08-13 17:24:35 +02:00
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										 |  |  |  | 第三个标签的文本应为 `310, 120`,`x` 值应为 `315`,`y` 值应为 `380`。 | 
					
						
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							|  |  |  |  | ```js | 
					
						
							|  |  |  |  | assert( | 
					
						
							|  |  |  |  |   $('text').eq(2).text() == '310, 120' && | 
					
						
							|  |  |  |  |     $('text').eq(2).attr('x') == '315' && | 
					
						
							|  |  |  |  |     $('text').eq(2).attr('y') == '380' | 
					
						
							|  |  |  |  | ); | 
					
						
							|  |  |  |  | ``` | 
					
						
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										 |  |  |  | 第四个标签的文本应为 `79, 411`,`x` 值应为 `84`,`y` 值应为 `89`。 | 
					
						
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							|  |  |  |  | ```js | 
					
						
							|  |  |  |  | assert( | 
					
						
							|  |  |  |  |   $('text').eq(3).text() == '79, 411' && | 
					
						
							|  |  |  |  |     $('text').eq(3).attr('x') == '84' && | 
					
						
							|  |  |  |  |     $('text').eq(3).attr('y') == '89' | 
					
						
							|  |  |  |  | ); | 
					
						
							|  |  |  |  | ``` | 
					
						
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										 |  |  |  | 第五个标签的文本应为 `420, 220`,`x` 值应为 `425`,`y` 值应为 `280`。 | 
					
						
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							|  |  |  |  | ```js | 
					
						
							|  |  |  |  | assert( | 
					
						
							|  |  |  |  |   $('text').eq(4).text() == '420, 220' && | 
					
						
							|  |  |  |  |     $('text').eq(4).attr('x') == '425' && | 
					
						
							|  |  |  |  |     $('text').eq(4).attr('y') == '280' | 
					
						
							|  |  |  |  | ); | 
					
						
							|  |  |  |  | ``` | 
					
						
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										 |  |  |  | 第六个标签的文本应为 `233, 145`,`x` 值应为 `238`,`y` 值应为 `355`。 | 
					
						
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							|  |  |  |  | ```js | 
					
						
							|  |  |  |  | assert( | 
					
						
							|  |  |  |  |   $('text').eq(5).text() == '233, 145' && | 
					
						
							|  |  |  |  |     $('text').eq(5).attr('x') == '238' && | 
					
						
							|  |  |  |  |     $('text').eq(5).attr('y') == '355' | 
					
						
							|  |  |  |  | ); | 
					
						
							|  |  |  |  | ``` | 
					
						
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										 |  |  |  | 第七个标签的文本应为 `333, 96`,`x` 值应为 `338`,`y` 值应为 `404`。 | 
					
						
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							|  |  |  |  | ```js | 
					
						
							|  |  |  |  | assert( | 
					
						
							|  |  |  |  |   $('text').eq(6).text() == '333, 96' && | 
					
						
							|  |  |  |  |     $('text').eq(6).attr('x') == '338' && | 
					
						
							|  |  |  |  |     $('text').eq(6).attr('y') == '404' | 
					
						
							|  |  |  |  | ); | 
					
						
							|  |  |  |  | ``` | 
					
						
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										 |  |  |  | 第八个标签的文本应为 `222, 333`,`x` 值应为 `227`,`y` 值应为 `167`。 | 
					
						
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							|  |  |  |  | ```js | 
					
						
							|  |  |  |  | assert( | 
					
						
							|  |  |  |  |   $('text').eq(7).text() == '222, 333' && | 
					
						
							|  |  |  |  |     $('text').eq(7).attr('x') == '227' && | 
					
						
							|  |  |  |  |     $('text').eq(7).attr('y') == '167' | 
					
						
							|  |  |  |  | ); | 
					
						
							|  |  |  |  | ``` | 
					
						
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										 |  |  |  | 第九个标签的文本应为 `78, 320`,`x` 值应为 `83`,`y` 值应为 `180`。 | 
					
						
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 | 
					
						
							|  |  |  |  | ```js | 
					
						
							|  |  |  |  | assert( | 
					
						
							|  |  |  |  |   $('text').eq(8).text() == '78, 320' && | 
					
						
							|  |  |  |  |     $('text').eq(8).attr('x') == '83' && | 
					
						
							|  |  |  |  |     $('text').eq(8).attr('y') == '180' | 
					
						
							|  |  |  |  | ); | 
					
						
							|  |  |  |  | ``` | 
					
						
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										 |  |  |  | 第十个标签的文本应为 `21, 123`,`x` 值应为 `26`,`y` 值应为 `377`。 | 
					
						
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							|  |  |  |  | ```js | 
					
						
							|  |  |  |  | assert( | 
					
						
							|  |  |  |  |   $('text').eq(9).text() == '21, 123' && | 
					
						
							|  |  |  |  |     $('text').eq(9).attr('x') == '26' && | 
					
						
							|  |  |  |  |     $('text').eq(9).attr('y') == '377' | 
					
						
							|  |  |  |  | ); | 
					
						
							|  |  |  |  | ``` | 
					
						
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										 |  |  |  | # --seed--
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							|  |  |  |  | 
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							|  |  |  |  | ## --seed-contents--
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							|  |  |  |  | ```html | 
					
						
							|  |  |  |  | <body> | 
					
						
							|  |  |  |  |   <script> | 
					
						
							|  |  |  |  |     const dataset = [ | 
					
						
							|  |  |  |  |                   [ 34,    78 ], | 
					
						
							|  |  |  |  |                   [ 109,   280 ], | 
					
						
							|  |  |  |  |                   [ 310,   120 ], | 
					
						
							|  |  |  |  |                   [ 79,    411 ], | 
					
						
							|  |  |  |  |                   [ 420,   220 ], | 
					
						
							|  |  |  |  |                   [ 233,   145 ], | 
					
						
							|  |  |  |  |                   [ 333,   96 ], | 
					
						
							|  |  |  |  |                   [ 222,   333 ], | 
					
						
							|  |  |  |  |                   [ 78,    320 ], | 
					
						
							|  |  |  |  |                   [ 21,    123 ] | 
					
						
							|  |  |  |  |                 ]; | 
					
						
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 | 
					
						
							|  |  |  |  | 
 | 
					
						
							|  |  |  |  |     const w = 500; | 
					
						
							|  |  |  |  |     const h = 500; | 
					
						
							|  |  |  |  | 
 | 
					
						
							|  |  |  |  |     const svg = d3.select("body") | 
					
						
							|  |  |  |  |                   .append("svg") | 
					
						
							|  |  |  |  |                   .attr("width", w) | 
					
						
							|  |  |  |  |                   .attr("height", h); | 
					
						
							|  |  |  |  | 
 | 
					
						
							|  |  |  |  |     svg.selectAll("circle") | 
					
						
							|  |  |  |  |        .data(dataset) | 
					
						
							|  |  |  |  |        .enter() | 
					
						
							|  |  |  |  |        .append("circle") | 
					
						
							|  |  |  |  |        .attr("cx", (d, i) => d[0]) | 
					
						
							|  |  |  |  |        .attr("cy", (d, i) => h - d[1]) | 
					
						
							|  |  |  |  |        .attr("r", 5); | 
					
						
							|  |  |  |  | 
 | 
					
						
							|  |  |  |  |     svg.selectAll("text") | 
					
						
							|  |  |  |  |        .data(dataset) | 
					
						
							|  |  |  |  |        .enter() | 
					
						
							|  |  |  |  |        .append("text") | 
					
						
							|  |  |  |  |        // Add your code below this line | 
					
						
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							|  |  |  |  | 
 | 
					
						
							|  |  |  |  |        // Add your code above this line | 
					
						
							|  |  |  |  |   </script> | 
					
						
							|  |  |  |  | </body> | 
					
						
							|  |  |  |  | ``` | 
					
						
							|  |  |  |  | 
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										 |  |  |  | # --solutions--
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							|  |  |  |  | 
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										 |  |  |  | ```html | 
					
						
							|  |  |  |  | <body> | 
					
						
							|  |  |  |  |   <script> | 
					
						
							|  |  |  |  |     const dataset = [ | 
					
						
							|  |  |  |  |                   [ 34,    78 ], | 
					
						
							|  |  |  |  |                   [ 109,   280 ], | 
					
						
							|  |  |  |  |                   [ 310,   120 ], | 
					
						
							|  |  |  |  |                   [ 79,    411 ], | 
					
						
							|  |  |  |  |                   [ 420,   220 ], | 
					
						
							|  |  |  |  |                   [ 233,   145 ], | 
					
						
							|  |  |  |  |                   [ 333,   96 ], | 
					
						
							|  |  |  |  |                   [ 222,   333 ], | 
					
						
							|  |  |  |  |                   [ 78,    320 ], | 
					
						
							|  |  |  |  |                   [ 21,    123 ] | 
					
						
							|  |  |  |  |                 ]; | 
					
						
							|  |  |  |  | 
 | 
					
						
							|  |  |  |  | 
 | 
					
						
							|  |  |  |  |     const w = 500; | 
					
						
							|  |  |  |  |     const h = 500; | 
					
						
							|  |  |  |  | 
 | 
					
						
							|  |  |  |  |     const svg = d3.select("body") | 
					
						
							|  |  |  |  |                   .append("svg") | 
					
						
							|  |  |  |  |                   .attr("width", w) | 
					
						
							|  |  |  |  |                   .attr("height", h); | 
					
						
							|  |  |  |  | 
 | 
					
						
							|  |  |  |  |     svg.selectAll("circle") | 
					
						
							|  |  |  |  |        .data(dataset) | 
					
						
							|  |  |  |  |        .enter() | 
					
						
							|  |  |  |  |        .append("circle") | 
					
						
							|  |  |  |  |        .attr("cx", (d, i) => d[0]) | 
					
						
							|  |  |  |  |        .attr("cy", (d, i) => h - d[1]) | 
					
						
							|  |  |  |  |        .attr("r", 5); | 
					
						
							|  |  |  |  | 
 | 
					
						
							|  |  |  |  |     svg.selectAll("text") | 
					
						
							|  |  |  |  |        .data(dataset) | 
					
						
							|  |  |  |  |        .enter() | 
					
						
							|  |  |  |  |        .append("text") | 
					
						
							|  |  |  |  |        .attr("x", (d) => d[0] + 5) | 
					
						
							|  |  |  |  |        .attr("y", (d) => h - d[1]) | 
					
						
							|  |  |  |  |        .text((d) => (d[0] + ", " + d[1])) | 
					
						
							| 
									
										
										
										
											2021-02-06 04:42:36 +00:00
										 |  |  |  | 
 | 
					
						
							| 
									
										
										
										
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										 |  |  |  |   </script> | 
					
						
							|  |  |  |  | </body> | 
					
						
							|  |  |  |  | ``` |