154 lines
4.0 KiB
Markdown
154 lines
4.0 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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challengeType: 6
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forumTopicId: 301476
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dashedName: add-labels-to-d3-elements
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---
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# --description--
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D3 lets you label a graph element, such as a bar, using the SVG `text` element.
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Like the `rect` element, a `text` element needs to have `x` and `y` attributes, to place it on the SVG canvas. It also needs to access the data to display those values.
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D3 gives you a high level of control over how you label your bars.
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# --instructions--
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The code in the editor already binds the data to each new `text` element. First, append `text` nodes to the `svg`. Next, add attributes for the `x` and `y` coordinates. They should be calculated the same way as the `rect` ones, except the `y` value for the `text` should make the label sit 3 units higher than the bar. Finally, use the D3 `text()` method to set the label equal to the data point value.
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**Note:** For the label to sit higher than the bar, decide if the `y` value for the `text` should be 3 greater or 3 less than the `y` value for the bar.
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# --hints--
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The first `text` element should have a label of `12` and a `y` value of `61`.
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```js
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assert($('text').eq(0).text() == '12' && $('text').eq(0).attr('y') == '61');
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```
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The second `text` element should have a label of `31` and a `y` value of `4`.
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```js
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assert($('text').eq(1).text() == '31' && $('text').eq(1).attr('y') == '4');
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```
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The third `text` element should have a label of `22` and a `y` value of `31`.
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```js
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assert($('text').eq(2).text() == '22' && $('text').eq(2).attr('y') == '31');
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```
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The fourth `text` element should have a label of `17` and a `y` value of `46`.
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```js
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assert($('text').eq(3).text() == '17' && $('text').eq(3).attr('y') == '46');
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```
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The fifth `text` element should have a label of `25` and a `y` value of `22`.
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```js
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assert($('text').eq(4).text() == '25' && $('text').eq(4).attr('y') == '22');
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```
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The sixth `text` element should have a label of `18` and a `y` value of `43`.
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```js
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assert($('text').eq(5).text() == '18' && $('text').eq(5).attr('y') == '43');
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```
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The seventh `text` element should have a label of `29` and a `y` value of `10`.
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```js
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assert($('text').eq(6).text() == '29' && $('text').eq(6).attr('y') == '10');
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```
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The eighth `text` element should have a label of `14` and a `y` value of `55`.
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```js
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assert($('text').eq(7).text() == '14' && $('text').eq(7).attr('y') == '55');
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```
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The ninth `text` element should have a label of `9` and a `y` value of `70`.
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```js
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assert($('text').eq(8).text() == '9' && $('text').eq(8).attr('y') == '70');
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```
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# --seed--
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## --seed-contents--
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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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# --solutions--
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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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.append("text")
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.attr("x", (d, i) => i * 30)
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.attr("y", (d, i) => h - (3 * d) - 3)
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.text((d) => d)
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</script>
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<body>
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```
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