2018-10-10 22:03:03 +00:00
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---
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id: bd7123c9c448eddfaeb5bdef
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2021-03-15 03:20:39 +00:00
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title: 查找字符串的长度
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2018-10-10 22:03:03 +00:00
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challengeType: 1
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2020-04-29 10:29:13 +00:00
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videoUrl: 'https://scrimba.com/c/cvmqEAd'
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forumTopicId: 18182
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2021-01-13 02:31:00 +00:00
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dashedName: find-the-length-of-a-string
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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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2018-10-10 22:03:03 +00:00
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2021-03-15 03:20:39 +00:00
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你可以通过在字符串变量或字符串后面写上 `.length` 来获得 `String` 的长度。
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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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```js
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console.log("Alan Peter".length);
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```
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字符串 `10` 将会出现在控制台中。
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2018-10-10 22:03:03 +00:00
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2021-11-06 15:56:52 +00:00
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例如,如果我们创建了一个变量 `const firstName = "Ada"`,我们可以通过使用 `firstName.length` 找出字符串 `Ada` 的长度属性。
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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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# --instructions--
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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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使用 `.length` 属性来获得变量 `lastName` 的长度,并把它赋值给变量 `lastNameLength`。
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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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# --hints--
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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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不能改变 `// Setup` 部分声明的变量。
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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(
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2021-11-06 15:56:52 +00:00
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code.match(/let lastNameLength = 0;/) &&
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code.match(/const lastName = "Lovelace";/)
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2020-12-16 07:37:30 +00:00
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);
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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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`lastNameLength` 应该等于 8。
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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(typeof lastNameLength !== 'undefined' && lastNameLength === 8);
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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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你应该使用 `.length` 获取 `lastName` 的长度,像这样 `lastName.length`。
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2020-04-29 10:29:13 +00:00
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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(code.match(/=\s*lastName\.length/g) && !code.match(/lastName\s*=\s*8/));
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2018-10-10 22:03:03 +00:00
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```
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2020-04-29 10:29:13 +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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// Setup
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2021-11-06 15:56:52 +00:00
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let lastNameLength = 0;
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const lastName = "Lovelace";
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2021-01-13 02:31:00 +00:00
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// Only change code below this line
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lastNameLength = lastName;
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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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2021-11-06 15:56:52 +00:00
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let lastNameLength = 0;
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const lastName = "Lovelace";
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2021-01-13 02:31:00 +00:00
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lastNameLength = lastName.length;
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```
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