71 lines
2.3 KiB
Markdown
71 lines
2.3 KiB
Markdown
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---
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id: 56bbb991ad1ed5201cd392cc
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title: Manipulate Arrays With pop()
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challengeType: 1
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videoUrl: ''
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localeTitle: 使用pop（）操作数组
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---
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## Description
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<section id="description">更改数组中数据的另一种方法是使用<code>.pop()</code>函数。 <code>.pop()</code>用于“弹出”数组末尾的值。我们可以通过将其赋值给变量来存储这个“弹出”值。换句话说， <code>.pop()</code>从数组中删除最后一个元素并返回该元素。任何类型的条目都可以从数组“弹出” - 数字，字符串，甚至嵌套数组。 <blockquote> <code>var threeArr = [1, 4, 6]; <br> var oneDown = threeArr.pop(); <br> console.log(oneDown); // Returns 6 <br> console.log(threeArr); // Returns [1, 4]</code> </blockquote> </section>
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## Instructions
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<section id="instructions">使用<code>.pop()</code>函数从<code>myArray</code>删除最后一项，将“弹出”值分配给<code>removedFromMyArray</code> 。 </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>myArray</code>应该只包含<code>[["John", 23]]</code> 。'
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testString: 'assert((function(d){if(d[0][0] == "John" && d[0][1] === 23 && d[1] == undefined){return true;}else{return false;}})(myArray), "<code>myArray</code> should only contain <code>[["John", 23]]</code>.");'
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- text: 在<code>myArray</code>上使用<code>pop()</code>
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testString: 'assert(/removedFromMyArray\s*=\s*myArray\s*.\s*pop\s*(\s*)/.test(code), "Use <code>pop()</code> on <code>myArray</code>");'
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- text: '<code>removedFromMyArray</code>应该只包含<code>["cat", 2]</code> 。'
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testString: 'assert((function(d){if(d[0] == "cat" && d[1] === 2 && d[2] == undefined){return true;}else{return false;}})(removedFromMyArray), "<code>removedFromMyArray</code> should only contain <code>["cat", 2]</code>.");'
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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 = [1,2,3];
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var removedFromOurArray = ourArray.pop();
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// removedFromOurArray now equals 3, and ourArray now equals [1,2]
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// Setup
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var myArray = [["John", 23], ["cat", 2]];
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// Only change code below this line.
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var removedFromMyArray;
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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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