2018-10-10 18:03:03 -04:00
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---
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id: 56533eb9ac21ba0edf2244b7
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2020-12-16 00:37:30 -07:00
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title: 用加号运算符连接字符串
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2018-10-10 18:03:03 -04:00
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challengeType: 1
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2020-04-29 18:29:13 +08:00
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videoUrl: 'https://scrimba.com/c/cNpM8AN'
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forumTopicId: 16802
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2018-10-10 18:03:03 -04:00
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---
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2020-12-16 00:37:30 -07:00
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# --description--
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在 JavaScript 中,当对一个`String`类型的值使用`+`操作符的时候,它被称作 <dfn>拼接操作符</dfn>。你可以通过<dfn>拼接</dfn>其他字符串来创建一个新的字符串。
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**示例**
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2020-04-29 18:29:13 +08:00
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```js
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'My name is Alan,' + ' I concatenate.'
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```
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2020-12-16 00:37:30 -07:00
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**提示**
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注意空格。拼接操作不会在两个字符串之间添加空格,所以想加上空格的话,你需要自己在字符串里面添加。
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2018-10-10 18:03:03 -04:00
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2020-12-16 00:37:30 -07:00
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# --instructions--
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2018-10-10 18:03:03 -04:00
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2020-12-16 00:37:30 -07:00
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使用`+`操作符,把字符串`"This is the start. "`和`"This is the end."`连接起来并赋值给变量`myStr`。
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2018-10-10 18:03:03 -04:00
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2020-12-16 00:37:30 -07:00
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# --hints--
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2018-10-10 18:03:03 -04:00
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2020-12-16 00:37:30 -07:00
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`myStr`的值应该是`This is the start. This is the end.`。
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2018-10-10 18:03:03 -04:00
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```js
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assert(myStr === 'This is the start. This is the end.');
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2018-10-10 18:03:03 -04:00
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```
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2020-12-16 00:37:30 -07:00
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使用`+`操作符构建`myStr`。
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2018-10-10 18:03:03 -04:00
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```js
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assert(code.match(/(["']).*(["'])\s*\+\s*(["']).*(["'])/g).length > 1);
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2018-10-10 18:03:03 -04:00
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```
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2020-12-16 00:37:30 -07:00
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`myStr`应该被`var`关键字声明。
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2018-10-10 18:03:03 -04:00
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2020-12-16 00:37:30 -07:00
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```js
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assert(/var\s+myStr/.test(code));
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```
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2018-10-10 18:03:03 -04:00
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2020-12-16 00:37:30 -07:00
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确保有给`myStr`赋值。
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2020-04-29 18:29:13 +08:00
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2018-10-10 18:03:03 -04:00
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```js
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assert(/myStr\s*=/.test(code));
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2018-10-10 18:03:03 -04:00
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```
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2020-04-29 18:29:13 +08:00
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2020-12-16 00:37:30 -07:00
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# --solutions--
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