62 lines
2.5 KiB
Markdown
62 lines
2.5 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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localeTitle: Emparejar patrones de cuerdas que comienzan
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challengeType: 1
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---
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## Description
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<section id='description'>
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Los desafíos anteriores mostraron que las expresiones regulares se pueden usar para buscar una serie de coincidencias. También se utilizan para buscar patrones en posiciones específicas en cadenas.
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En un desafío anterior, <code>caret</code> carácter de <code>caret</code> ( <code>^</code> ) dentro de un <code>character set</code> para crear un <code>negated character set</code> en la forma <code>[^thingsThatWillNotBeMatched]</code> . Fuera de un <code>character set</code> , el <code>caret</code> se utiliza para buscar patrones al principio de las cadenas.
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<blockquote>let firstString = "Ricky is first and can be found.";<br>let firstRegex = /^Ricky/;<br>firstRegex.test(firstString);<br>// Returns true<br>let notFirst = "You can't find Ricky now.";<br>firstRegex.test(notFirst);<br>// Returns false</blockquote>
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</section>
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## Instructions
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<section id='instructions'>
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Use el carácter de <code>caret</code> en una expresión regular para encontrar <code>"Cal"</code> solo al principio de la cadena <code>rickyAndCal</code> .
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</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: Su expresión regular debe buscar <code>"Cal"</code> con una letra mayúscula.
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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: Su expresión regular no debe usar ninguna bandera.
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testString: 'assert(calRegex.flags == "", "Your regex should not use any flags.");'
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- text: Tu expresión regular debe coincidir con <code>"Cal"</code> al principio de la cadena.
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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: Su expresión regular no debe coincidir con <code>"Cal"</code> en medio de una cadena.
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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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