2018-10-10 22:03:03 +00:00
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---
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id: 56533eb9ac21ba0edf2244d6
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2021-03-13 17:31:57 +00:00
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title: 小于运算符
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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/cNVRWtB'
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forumTopicId: 16789
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2021-01-13 02:31:00 +00:00
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dashedName: comparison-with-the-less-than-operator
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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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2021-03-13 17:31:57 +00:00
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使用小于运算符(`<`)来比较两个数字。 如果小于运算符左边的数字比右边的数字小,它会返回 `true`。 否则会返回 `false`。 与相等运算符类似,小于运算符在做比较的时候会转换值的数据类型。
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2020-12-16 07:37:30 +00:00
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2021-03-13 17:31:57 +00:00
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**例如:**
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2020-04-29 10:29:13 +00:00
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```js
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2021-03-13 17:31:57 +00:00
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2 < 5
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'3' < 7
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5 < 5
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3 < 2
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'8' < 4
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2020-04-29 10:29:13 +00:00
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```
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2021-03-13 17:31:57 +00:00
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按顺序,这些表达式会返回 `true`、`true`、`false`、`false` 和 `false`。
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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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2021-03-13 17:31:57 +00:00
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添加小于运算符到指定行,使得函数的返回语句有意义。
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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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2021-03-13 17:31:57 +00:00
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`testLessThan(0)` 应该返回字符串 `Under 25`。
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2018-10-10 22:03:03 +00:00
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```js
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assert(testLessThan(0) === 'Under 25');
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```
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2018-10-10 22:03:03 +00:00
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2021-03-13 17:31:57 +00:00
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`testLessThan(24)` 应该返回字符串 `Under 25`。
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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(testLessThan(24) === 'Under 25');
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2018-10-10 22:03:03 +00:00
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```
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2021-03-13 17:31:57 +00:00
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`testLessThan(25)` 应该返回字符串 `Under 55`。
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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(testLessThan(25) === 'Under 55');
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```
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2018-10-10 22:03:03 +00:00
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2021-03-13 17:31:57 +00:00
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`testLessThan(54)` 应该返回字符串 `Under 55`。
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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(testLessThan(54) === 'Under 55');
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```
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2018-10-10 22:03:03 +00:00
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2021-03-13 17:31:57 +00:00
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`testLessThan(55)` 应该返回字符串 `55 or Over`。
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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(testLessThan(55) === '55 or Over');
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```
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`testLessThan(99)` 应该返回字符串 `55 or Over`。
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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(testLessThan(99) === '55 or Over');
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```
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2020-04-29 10:29:13 +00:00
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2021-03-13 17:31:57 +00:00
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应该使用 `<` 运算符至少两次。
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2020-04-29 10:29:13 +00:00
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2020-12-16 07:37:30 +00:00
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```js
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assert(code.match(/val\s*<\s*('|")*\d+('|")*/g).length > 1);
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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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function testLessThan(val) {
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if (val) { // Change this line
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return "Under 25";
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}
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if (val) { // Change this line
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return "Under 55";
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}
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return "55 or Over";
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}
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testLessThan(10);
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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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function testLessThan(val) {
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if (val < 25) { // Change this line
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return "Under 25";
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}
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if (val < 55) { // Change this line
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return "Under 55";
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}
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return "55 or Over";
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}
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```
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