68 lines
1.7 KiB
Markdown
68 lines
1.7 KiB
Markdown
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---
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id: 56bbb991ad1ed5201cd392ce
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title: Manipulate Arrays With unshift()
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challengeType: 1
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videoUrl: ''
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localeTitle: 使用unshift操作数组（）
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---
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## Description
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<section id="description">不仅可以<code>shift</code>元件关闭的阵列的开头的，也可以<code>unshift</code>元素添加到数组的开始，即在阵列的前添加元素。 <code>.unshift()</code>工作方式与<code>.push()</code>完全相同，但是不是在数组的末尾添加元素， <code>unshift()</code>会在数组的开头添加元素。 </section>
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## Instructions
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<section id="instructions">使用<code>unshift()</code>将<code>["Paul",35]</code>添加到<code>myArray</code>变量的开头。 </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>现在应该有[[“Paul”，35]，[“dog”，3]]。'
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testString: 'assert((function(d){if(typeof d[0] === "object" && d[0][0] == "Paul" && d[0][1] === 35 && d[1][0] != undefined && d[1][0] == "dog" && d[1][1] != undefined && d[1][1] == 3){return true;}else{return false;}})(myArray), "<code>myArray</code> should now have [["Paul", 35], ["dog", 3]].");'
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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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ourArray.shift(); // ourArray now equals ["J", "cat"]
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ourArray.unshift("Happy");
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// ourArray now equals ["Happy", "J", "cat"]
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// Setup
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var myArray = [["John", 23], ["dog", 3]];
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myArray.shift();
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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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