2018-10-10 22:03:03 +00:00
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---
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id: 587d7b7e367417b2b2512b24
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2021-03-15 03:20:39 +00:00
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title: 使用三元运算符
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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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forumTopicId: 301181
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2021-01-13 02:31:00 +00:00
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dashedName: use-the-conditional-ternary-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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2021-03-15 03:20:39 +00:00
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条件运算符( <dfn>conditional operator</dfn>,)(也称为三元运算符( <dfn>ternary operator</dfn>))的就像写成一行的 if-else 表达式
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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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语法是 `a ? b: c`,其中 `a` 是条件,`b` 是条件返回 `true` 时要运行的代码,`c` 是条件返回 `false` 时要运行的代码。
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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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以下函数使用 `if/else` 语句来检查条件:
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2020-04-29 10:29:13 +00:00
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```js
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function findGreater(a, b) {
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if(a > b) {
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return "a is greater";
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}
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else {
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return "b is greater";
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}
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}
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```
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2021-03-15 03:20:39 +00:00
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这可以使用三元运算符重写:
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2020-04-29 10:29:13 +00:00
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```js
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function findGreater(a, b) {
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return a > b ? "a is greater" : "b is greater";
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}
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```
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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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在 `checkEqual` 函数中使用三元运算符检查两个数字是否相等。 函数应该返回 `Equal` 或字符串 `Not Equal`。
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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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`checkEqual` 应该使用条件运算符。
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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(/.+?\s*?\?\s*?.+?\s*?:\s*?.+?/.test(code));
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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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`checkEqual(1, 2)` 应该返回字符串 `Not Equal`
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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(checkEqual(1, 2) === 'Not Equal');
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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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`checkEqual(1, 1)` 应该返回字符串 `Equal`
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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(checkEqual(1, 1) === 'Equal');
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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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`checkEqual(1, -1)` 应该返回字符串 `Not Equal`
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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(checkEqual(1, -1) === 'Not Equal');
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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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function checkEqual(a, b) {
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}
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checkEqual(1, 2);
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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 checkEqual(a, b) {
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return a === b ? "Equal" : "Not Equal";
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}
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```
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