69 lines
1.9 KiB
Markdown
69 lines
1.9 KiB
Markdown
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---
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id: 56bbb991ad1ed5201cd392cd
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title: Manipulate Arrays With shift()
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challengeType: 1
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videoUrl: ''
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localeTitle: 使用shift（）操纵数组
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---
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## Description
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<section id="description"> <code>pop()</code>总是删除数组的最后一个元素。如果你想删除第一个怎么办？这就是<code>.shift()</code>用武之地。它就像<code>.pop()</code>一样工作，除了它删除了第一个元素而不是最后一个元素。 </section>
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## Instructions
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<section id="instructions">使用<code>.shift()</code>函数从<code>myArray</code>删除第一项，将“shift off”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>现在应该等于<code>[["dog", 3]]</code> 。'
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testString: 'assert((function(d){if(d[0][0] == "dog" && d[0][1] === 3 && d[1] == undefined){return true;}else{return false;}})(myArray), "<code>myArray</code> should now equal <code>[["dog", 3]]</code>.");'
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- text: '<code>removedFromMyArray</code>应该包含<code>["John", 23]</code> 。'
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testString: 'assert((function(d){if(d[0] == "John" && d[1] === 23 && typeof removedFromMyArray === "object"){return true;}else{return false;}})(removedFromMyArray), "<code>removedFromMyArray</code> should contain <code>["John", 23]</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 = ["Stimpson", "J", ["cat"]];
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var removedFromOurArray = ourArray.shift();
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// removedFromOurArray now equals "Stimpson" and ourArray now equals ["J", ["cat"]].
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// Setup
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var myArray = [["John", 23], ["dog", 3]];
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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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