59 lines
2.3 KiB
Markdown
59 lines
2.3 KiB
Markdown
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---
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id: 587d7b7a367417b2b2512b12
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title: Copy Array Items Using slice()
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challengeType: 1
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videoUrl: ''
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localeTitle: 使用slice（）复制数组项
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---
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## Description
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<section id="description">我们将介绍的下一个方法是<code>slice()</code> 。 <code>slice()</code> ，而不是修改数组，将给定数量的元素复制或<em>提取</em>到新数组，而不改变它所调用的数组。 <code>slice()</code>只接受2个参数 - 第一个是开始提取的索引，第二个是停止提取的索引（提取将发生，但不包括此索引处的元素）。考虑一下： <blockquote>让weatherConditions = ['rain'，'snow'，'sleet'，'hail'，'clear']; <br><br>让todaysWeather = weatherConditions.slice（1,3）; <br> //今天天气等于['雪'，'雨夹雪']; <br> // weatherConditions仍等于['rain'，'snow'，'sleet'，'hail'，'clear'] <br></blockquote>实际上，我们通过从现有数组中提取元素来创建一个新数组。 </section>
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## Instructions
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<section id="instructions">我们定义了一个以数组作为参数的函数<code>forecast</code> 。使用<code>slice()</code>修改函数以从参数数组中提取信息，并返回包含元素<code>'warm'</code>和<code>'sunny'</code>的新数组。 </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: '<code>forecast</code>应该返回<code>["warm", "sunny"]</code>'
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testString: 'assert.deepEqual(forecast(["cold", "rainy", "warm", "sunny", "cool", "thunderstorms"]), ["warm", "sunny"], "<code>forecast</code> should return <code>["warm", "sunny"]");'
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- text: <code>forecast</code>函数应该使用<code>slice()</code>方法
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testString: 'assert(/\.slice\(/.test(code), "The <code>forecast</code> function should utilize the <code>slice()</code> method");'
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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='js-seed'>
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```js
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function forecast(arr) {
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// change code below this line
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return arr;
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}
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// do not change code below this line
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console.log(forecast(['cold', 'rainy', 'warm', 'sunny', 'cool', 'thunderstorms']));
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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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