ee1e8abd87
* feat(tools): add seed/solution restore script * chore(curriculum): remove empty sections' markers * chore(curriculum): add seed + solution to Chinese * chore: remove old formatter * fix: update getChallenges parse translated challenges separately, without reference to the source * chore(curriculum): add dashedName to English * chore(curriculum): add dashedName to Chinese * refactor: remove unused challenge property 'name' * fix: relax dashedName requirement * fix: stray tag Remove stray `pre` tag from challenge file. Signed-off-by: nhcarrigan <nhcarrigan@gmail.com> Co-authored-by: nhcarrigan <nhcarrigan@gmail.com>
86 lines
1.7 KiB
Markdown
86 lines
1.7 KiB
Markdown
---
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id: 587d7db9367417b2b2512ba7
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title: 指定匹配的确切数量
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challengeType: 1
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forumTopicId: 301365
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dashedName: specify-exact-number-of-matches
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---
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# --description--
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可以使用带有花括号的`数量说明符`来指定匹配模式的上下限。但有时只需要特定数量的匹配。
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要指定一定数量的匹配模式，只需在大括号之间放置一个数字。
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例如，要只匹配字母`a`出现`3`次的单词`"hah"`，正则表达式应为`/ha{3}h/`。
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```js
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let A4 = "haaaah";
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let A3 = "haaah";
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let A100 = "h" + "a".repeat(100) + "h";
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let multipleHA = /ha{3}h/;
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multipleHA.test(A4); // Returns false
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multipleHA.test(A3); // Returns true
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multipleHA.test(A100); // Returns false
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```
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# --instructions--
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修改正则表达式`timRegex`，以匹配仅有四个字母单词`m`的单词`"Timber"`。
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# --hints--
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你的正则表达式应该使用花括号。
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```js
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assert(timRegex.source.match(/{.*?}/).length > 0);
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```
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你的正则表达式不应该匹配`'Timber'`。
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```js
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assert(!timRegex.test('Timber'));
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```
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你的正则表达式不应该匹配`'Timmber'`。
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```js
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assert(!timRegex.test('Timmber'));
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```
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你的正则表达式不应该匹配`'Timmmber'`。
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```js
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assert(!timRegex.test('Timmmber'));
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```
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你的正则表达式应该匹配`'Timmmmber'`。
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```js
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assert(timRegex.test('Timmmmber'));
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```
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你的正则表达式不应该匹配包含 30 个字母`m`的`'Timber'`。
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```js
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assert(!timRegex.test('Ti' + 'm'.repeat(30) + 'ber'));
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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 timStr = "Timmmmber";
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let timRegex = /change/; // Change this line
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let result = timRegex.test(timStr);
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```
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# --solutions--
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```js
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let timStr = "Timmmmber";
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let timRegex = /Tim{4}ber/; // Change this line
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let result = timRegex.test(timStr);
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```
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