freeCodeCamp/curriculum/challenges/chinese/02-javascript-algorithms-an.../regular-expressions/specify-upper-and-lower-num...

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---
id: 587d7db9367417b2b2512ba5
title: Specify Upper and Lower Number of Matches
challengeType: 1
videoUrl: ''
localeTitle: 指定上下匹配数
---
## Description
<section id="description">回想一下,您使用加号<code>+</code>来查找一个或多个字符,使用星号<code>*</code>来查找零个或多个字符。这些很方便,但有时你想要匹配一定范围的模式。您可以使用<code>quantity specifiers</code>模式的下限和上限。数量说明符与大括号( <code>{</code><code>}</code> )一起使用。您在大括号之间放置了两个数字 - 用于较低和较高的模式数。例如,为了匹配字母<code>&quot;ah&quot;</code>出现<code>3</code><code>5</code>次的字母<code>a</code> ,你的正则表达式将是<code>/a{3,5}h/</code><blockquote>让A4 =“aaaah”; <br>让A2 =“aah”; <br>令multipleA = / a {3,5} h /; <br> multipleA.testA4; //返回true <br> multipleA.testA2; //返回false </blockquote></section>
## Instructions
<section id="instructions">更改正则表达式<code>ohRegex</code>以匹配单词<code>&quot;Oh no&quot;</code>中的<code>3</code><code>6</code>字母<code>h</code></section>
## Tests
<section id='tests'>
```yml
tests:
- text: 你的正则表达式应该使用大括号。
testString: 'assert(ohRegex.source.match(/{.*?}/).length > 0, "Your regex should use curly brackets.");'
- text: 你的正则表达式不应该匹配<code>&quot;Ohh no&quot;</code>
testString: 'assert(!ohRegex.test("Ohh no"), "Your regex should not match <code>"Ohh no"</code>");'
- text: 你的正则表达式应该匹配<code>&quot;Ohhh no&quot;</code>
testString: 'assert(ohRegex.test("Ohhh no"), "Your regex should match <code>"Ohhh no"</code>");'
- text: 你的正则表达式应该匹配<code>&quot;Ohhhh no&quot;</code>
testString: 'assert(ohRegex.test("Ohhhh no"), "Your regex should match <code>"Ohhhh no"</code>");'
- text: 你的正则表达式应该匹配<code>&quot;Ohhhhh no&quot;</code>
testString: 'assert(ohRegex.test("Ohhhhh no"), "Your regex should match <code>"Ohhhhh no"</code>");'
- text: 你的正则表达式应该匹配<code>&quot;Ohhhhhh no&quot;</code>
testString: 'assert(ohRegex.test("Ohhhhhh no"), "Your regex should match <code>"Ohhhhhh no"</code>");'
- text: 你的正则表达式不应该匹配<code>&quot;Ohhhhhhh no&quot;</code>
testString: 'assert(!ohRegex.test("Ohhhhhhh no"), "Your regex should not match <code>"Ohhhhhhh no"</code>");'
```
</section>
## Challenge Seed
<section id='challengeSeed'>
<div id='js-seed'>
```js
let ohStr = "Ohhh no";
let ohRegex = /change/; // Change this line
let result = ohRegex.test(ohStr);
```
</div>
</section>
## Solution
<section id='solution'>
```js
// solution required
```
</section>