2018-10-10 22:03:03 +00:00
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---
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id: 587d7db9367417b2b2512ba6
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2021-03-15 03:20:39 +00:00
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title: 只指定匹配的下限
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2018-10-10 22:03:03 +00:00
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challengeType: 1
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2020-08-04 07:14:01 +00:00
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forumTopicId: 301366
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2021-01-13 02:31:00 +00:00
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dashedName: specify-only-the-lower-number-of-matches
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2018-10-10 22:03:03 +00:00
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---
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2020-12-16 07:37:30 +00:00
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# --description--
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2021-03-15 03:20:39 +00:00
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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。 但有时候只想指定匹配模式的下限而不需要指定上限。
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2020-12-16 07:37:30 +00:00
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2021-03-15 03:20:39 +00:00
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为此,在第一个数字后面跟一个逗号即可。
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2020-12-16 07:37:30 +00:00
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2021-03-15 03:20:39 +00:00
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例如,要匹配至少出现 `3` 次字母 `a` 的字符串 `hah`,正则表达式应该是 `/ha{3,}h/`。
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2020-08-04 07:14:01 +00:00
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```js
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let A4 = "haaaah";
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let A2 = "haah";
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let A100 = "h" + "a".repeat(100) + "h";
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let multipleA = /ha{3,}h/;
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2021-03-15 03:20:39 +00:00
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multipleA.test(A4);
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multipleA.test(A2);
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multipleA.test(A100);
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2020-08-04 07:14:01 +00:00
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```
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2021-03-15 03:20:39 +00:00
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按顺序排列,三次 `test` 调用将返回值 `true`,`false` 和 `true`。
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2020-12-16 07:37:30 +00:00
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# --instructions--
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2021-03-15 03:20:39 +00:00
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修改正则表达式 `haRegex`,匹配包含四个或更多字母 `z` 的单词 `Hazzah`。
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2020-12-16 07:37:30 +00:00
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# --hints--
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2021-03-15 03:20:39 +00:00
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你的正则表达式应该使用花括号。
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2020-12-16 07:37:30 +00:00
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```js
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assert(haRegex.source.match(/{.*?}/).length > 0);
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```
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2021-03-15 03:20:39 +00:00
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你的正则表达式不应匹配字符串 `Hazzah`
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2018-10-10 22:03:03 +00:00
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2020-12-16 07:37:30 +00:00
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```js
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assert(!haRegex.test('Hazzah'));
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2018-10-10 22:03:03 +00:00
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```
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2021-03-15 03:20:39 +00:00
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你的正则表达式不应匹配字符串 `Hazzzah`
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2018-10-10 22:03:03 +00:00
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2020-12-16 07:37:30 +00:00
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```js
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assert(!haRegex.test('Hazzzah'));
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```
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2018-10-10 22:03:03 +00:00
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2021-03-15 03:20:39 +00:00
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你的正则表达式应该匹配字符串 `Hazzzzah`
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2018-10-10 22:03:03 +00:00
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```js
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2020-12-16 07:37:30 +00:00
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assert('Hazzzzah'.match(haRegex)[0].length === 8);
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2018-10-10 22:03:03 +00:00
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```
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2021-03-15 03:20:39 +00:00
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你的正则表达式应该匹配字符串 `Hazzzzzah`
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2018-10-10 22:03:03 +00:00
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2020-12-16 07:37:30 +00:00
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```js
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assert('Hazzzzzah'.match(haRegex)[0].length === 9);
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```
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2018-10-10 22:03:03 +00:00
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2021-03-15 03:20:39 +00:00
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你的正则表达式应该匹配字符串 `Hazzzzzzah`
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2018-10-10 22:03:03 +00:00
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2020-12-16 07:37:30 +00:00
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```js
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assert('Hazzzzzzah'.match(haRegex)[0].length === 10);
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```
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2018-10-10 22:03:03 +00:00
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2021-03-15 03:20:39 +00:00
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你的正则表达式应该匹配包含 30 个字母 `z` 的 `Hazzah`。
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2018-10-10 22:03:03 +00:00
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```js
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2020-12-16 07:37:30 +00:00
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assert('Hazzzzzzzzzzzzzzzzzzzzzzzzzzzzzzah'.match(haRegex)[0].length === 34);
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2018-10-10 22:03:03 +00:00
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```
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2020-08-04 07:14:01 +00:00
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2021-01-13 02:31:00 +00:00
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# --seed--
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## --seed-contents--
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```js
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let haStr = "Hazzzzah";
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let haRegex = /change/; // Change this line
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let result = haRegex.test(haStr);
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```
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2020-12-16 07:37:30 +00:00
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# --solutions--
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2021-01-13 02:31:00 +00:00
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```js
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let haStr = "Hazzzzah";
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let haRegex = /Haz{4,}ah/; // Change this line
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let result = haRegex.test(haStr);
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```
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