74 lines
1.9 KiB
Markdown
74 lines
1.9 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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dashedName: match-beginning-string-patterns
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---
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# --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 caret character (`^`) inside a character set to create a negated character set in the form `[^thingsThatWillNotBeMatched]`. Outside of a character set, the caret 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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let notFirst = "You can't find Ricky now.";
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firstRegex.test(notFirst);
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```
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The first `test` call would return `true`, while the second would return `false`.
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# --instructions--
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Use the caret character in a regex to find `Cal` only in the beginning of the string `rickyAndCal`.
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# --hints--
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Your regex should search for the string `Cal` with a capital letter.
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```js
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assert(calRegex.source == '^Cal');
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```
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Your regex should not use any flags.
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```js
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assert(calRegex.flags == '');
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```
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Your regex should match the string `Cal` at the beginning of the string.
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```js
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calRegex.lastIndex = 0;
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assert(calRegex.test('Cal and Ricky both like racing.'));
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```
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Your regex should not match the string `Cal` in the middle of a string.
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```js
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calRegex.lastIndex = 0;
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assert(!calRegex.test('Ricky and Cal both like racing.'));
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```
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# --seed--
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## --seed-contents--
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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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# --solutions--
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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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