68 lines
2.2 KiB
Markdown
68 lines
2.2 KiB
Markdown
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---
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id: 56bbb991ad1ed5201cd392ca
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title: Access Array Data with Indexes
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challengeType: 1
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guideUrl: 'https://chinese.freecodecamp.org/guide/certificates/access-array-data-with-indexes'
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videoUrl: ''
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localeTitle: 使用索引访问数组数据
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---
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## Description
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<section id="description">我们可以使用<code>indexes</code>访问数组内部的数据。数组索引使用字符串使用的相同括号表示法编写，但不是指定字符，而是指定数组中的条目。与字符串一样，数组使用<dfn>从零开始的</dfn>索引，因此数组中的第一个元素是元素<code>0</code> 。 <strong>例</strong> <blockquote> var array = [50,60,70]; <br>阵列[0]; //等于50 <br> var data = array [1]; //等于60 </blockquote> <strong>注意</strong> <br>数组名称和方括号之间不应有任何空格，如<code>array [0]</code> 。尽管JavaScript能够正确处理，但这可能会让其他程序员在阅读代码时感到困惑。 </section>
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## Instructions
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<section id="instructions">创建一个名为<code>myData</code>的变量，并使用括号表示法将其设置为等于<code>myArray</code>的第一个值。 </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: 变量<code>myData</code>应该等于<code>myArray</code>的第一个值。
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testString: 'assert((function(){if(typeof myArray !== "undefined" && typeof myData !== "undefined" && myArray[0] === myData){return true;}else{return false;}})(), "The variable <code>myData</code> should equal the first value of <code>myArray</code>.");'
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- text: 应使用括号表示法访问变量<code>myArray</code>的数据。
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testString: 'assert((function(){if(code.match(/\s*=\s*myArray\[0\]/g)){return true;}else{return false;}})(), "The data in variable <code>myArray</code> should be accessed using bracket notation.");'
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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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// Example
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var ourArray = [50,60,70];
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var ourData = ourArray[0]; // equals 50
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// Setup
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var myArray = [50,60,70];
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// Only change code below this line.
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```
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</div>
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### After Test
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<div id='js-teardown'>
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```js
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console.info('after the test');
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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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