58 lines
2.3 KiB
Markdown
58 lines
2.3 KiB
Markdown
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---
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id: 587d7db7367417b2b2512b9d
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title: Match Beginning String Patterns
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challengeType: 1
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videoUrl: ''
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localeTitle: 匹配开始字符串模式
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---
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## Description
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<section id="description">先前的挑战表明，正则表达式可用于寻找许多匹配。它们还用于搜索字符串中特定位置的模式。在之前的挑战中，您使用<code>character set</code>内的<code>caret</code>符（ <code>^</code> ）来创建<code>[^thingsThatWillNotBeMatched]</code>形式的<code>negated character set</code> 。在<code>character set</code> ， <code>caret</code>用于在字符串的开头搜索模式。 <blockquote>让firstString =“Ricky是第一个，可以找到。”; <br>让firstRegex = / ^ Ricky /; <br> firstRegex.test（firstString）; <br> //返回true <br>让notFirst =“你现在找不到Ricky了。”; <br> firstRegex.test（notFirst）; <br> //返回false </blockquote></section>
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## Instructions
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<section id="instructions">使用正则表达式中的<code>caret</code>只能在字符串<code>rickyAndCal</code>的开头找到<code>"Cal"</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: 你的正则表达式应该用大写字母搜索<code>"Cal"</code> 。
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testString: 'assert(calRegex.source == "^Cal", "Your regex should search for <code>"Cal"</code> with a capital letter.");'
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- text: 你的正则表达式不应该使用任何标志。
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testString: 'assert(calRegex.flags == "", "Your regex should not use any flags.");'
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- text: 你的正则表达式应该匹配字符串开头的<code>"Cal"</code> 。
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testString: 'assert(calRegex.test("Cal and Ricky both like racing."), "Your regex should match <code>"Cal"</code> at the beginning of the string.");'
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- text: 您的正则表达式不应与字符串中间的<code>"Cal"</code>匹配。
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testString: 'assert(!calRegex.test("Ricky and Cal both like racing."), "Your regex should not match <code>"Cal"</code> in the middle of a string.");'
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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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let rickyAndCal = "Cal and Ricky both like racing.";
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let calRegex = /change/; // Change this line
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let result = calRegex.test(rickyAndCal);
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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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