61 lines
2.9 KiB
Markdown
61 lines
2.9 KiB
Markdown
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---
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id: 587d78b2367417b2b2512b0f
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title: Remove Items from an Array with pop() and shift()
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challengeType: 1
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videoUrl: ''
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localeTitle: 使用pop（）和shift（）从数组中删除项
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---
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## Description
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<section id="description"> <code>push()</code>和<code>unshift()</code>都有相应的几乎相反的方法： <code>pop()</code>和<code>shift()</code> 。正如您现在可能已经猜到的那样， <code>pop()</code>不是添加，而是从数组的末尾<em>删除</em>元素，而<code>shift()</code>从头开始删除元素。 <code>pop()</code>和<code>shift()</code>及其兄弟<code>push()</code>和<code>unshift()</code>之间的关键区别在于，两个方法都不接受参数，并且每个方法只允许一次由单个元素修改数组。让我们来看看： <blockquote>让问候= ['什么事情？'，'你好'，'看到你！']; <br><br> greetings.pop（）; <br> //现在等于['whats up？'，'hello'] <br><br> greetings.shift（）; <br> //现在等于['你好'] </blockquote>我们还可以使用以下任一方法返回已删除元素的值： <blockquote> let popped = greetings.pop（）; <br> //返回'你好' <br> //问候现在等于[] </blockquote></section>
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## Instructions
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<section id="instructions">我们定义了一个函数<code>popShift</code> ，它将一个数组作为参数并返回一个新数组。使用<code>pop()</code>和<code>shift()</code>修改函数，删除参数数组的第一个和最后一个元素，并将删除的元素分配给它们对应的变量，以便返回的数组包含它们的值。 </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: '<code>popShift(["challenge", "is", "not", "complete"])</code>应返回<code>["challenge", "complete"]</code>'
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testString: 'assert.deepEqual(popShift(["challenge", "is", "not", "complete"]), ["challenge", "complete"], "<code>popShift(["challenge", "is", "not", "complete"])</code> should return <code>["challenge", "complete"]</code>");'
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- text: <code>popShift</code>函数应该使用<code>pop()</code>方法
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testString: 'assert.notStrictEqual(popShift.toString().search(/\.pop\(/), -1, "The <code>popShift</code> function should utilize the <code>pop()</code> method");'
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- text: <code>popShift</code>函数应该使用<code>shift()</code>方法
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testString: 'assert.notStrictEqual(popShift.toString().search(/\.shift\(/), -1, "The <code>popShift</code> function should utilize the <code>shift()</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 popShift(arr) {
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let popped; // change this line
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let shifted; // change this line
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return [shifted, popped];
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}
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// do not change code below this line
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console.log(popShift(['challenge', 'is', 'not', 'complete']));
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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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