75 lines
2.1 KiB
Markdown
75 lines
2.1 KiB
Markdown
---
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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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forumTopicId: 301349
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---
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## Description
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<section id='description'>
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Prior challenges showed that regular expressions can be used to look for a number of matches. They are also used to search for patterns in specific positions in strings.
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In an earlier challenge, you used the <code>caret</code> character (<code>^</code>) inside a <code>character set</code> to create a <code>negated character set</code> in the form <code>[^thingsThatWillNotBeMatched]</code>. Outside of a <code>character set</code>, the <code>caret</code> is used to search for patterns at the beginning of strings.
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```js
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let firstString = "Ricky is first and can be found.";
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let firstRegex = /^Ricky/;
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firstRegex.test(firstString);
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// Returns true
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let notFirst = "You can't find Ricky now.";
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firstRegex.test(notFirst);
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// Returns false
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```
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</section>
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## Instructions
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<section id='instructions'>
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Use the <code>caret</code> character in a regex to find <code>"Cal"</code> only in the beginning of the string <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: Your regex should search for <code>"Cal"</code> with a capital letter.
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testString: assert(calRegex.source == "^Cal");
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- text: Your regex should not use any flags.
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testString: assert(calRegex.flags == "");
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- text: Your regex should match <code>"Cal"</code> at the beginning of the string.
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testString: assert(calRegex.test("Cal and Ricky both like racing."));
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- text: Your regex should not match <code>"Cal"</code> in the middle of a string.
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testString: assert(!calRegex.test("Ricky and Cal both like racing."));
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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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let rickyAndCal = "Cal and Ricky both like racing.";
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let calRegex = /^Cal/; // Change this line
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let result = calRegex.test(rickyAndCal);
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```
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</section>
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