70 lines
2.5 KiB
Markdown
70 lines
2.5 KiB
Markdown
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---
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id: cf1111c1c11feddfaeb5bdef
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title: Iterate with JavaScript For Loops
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challengeType: 1
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videoUrl: ''
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localeTitle: 使用JavaScript迭代循环
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---
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## Description
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<section id="description">您可以使用循环多次运行相同的代码。最常见的JavaScript循环类型称为“ <code>for loop</code> ”，因为它“运行”特定次数。 For循环用三个可选表达式声明，用分号分隔： <code>for ([initialization]; [condition]; [final-expression])</code> <code>initialization</code>语句仅在循环开始之前执行一次。它通常用于定义和设置循环变量。 <code>condition</code>语句在每次循环迭代开始时进行计算，并且只要计算结果为<code>true</code>就会继续。当迭代开始时<code>condition</code>为<code>false</code>时，循环将停止执行。这意味着如果<code>condition</code>以<code>false</code>开头，则循环将永远不会执行。 <code>final-expression</code>在每次循环迭代结束时执行，在下一次<code>condition</code>检查之前执行，通常用于递增或递减循环计数器。在下面的示例中，我们使用<code>i = 0</code>初始化并迭代，而条件<code>i < 5</code>为真。我们将在每个循环迭代中将<code>i</code>递增<code>1</code> ，并使用<code>i++</code>作为<code>final-expression</code> 。 <blockquote> var ourArray = []; <br> for（var i = 0; i <5; i ++）{ <br> ourArray.push（ⅰ）; <br> } </blockquote> <code>ourArray</code>现在包含<code>[0,1,2,3,4]</code> 。 </section>
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## Instructions
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<section id="instructions">使用<code>for</code>循环将值1到5推送到<code>myArray</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: 你应该为此使用<code>for</code>循环。
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testString: 'assert(code.match(/for\s*\(/g).length > 1, "You should be using a <code>for</code> loop for this.");'
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- text: '<code>myArray</code>应该等于<code>[1,2,3,4,5]</code> 。'
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testString: 'assert.deepEqual(myArray, [1,2,3,4,5], "<code>myArray</code> should equal <code>[1,2,3,4,5]</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 = [];
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for (var i = 0; i < 5; i++) {
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ourArray.push(i);
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}
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// Setup
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var myArray = [];
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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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