2021-05-05 10:13:49 -07:00
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---
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id: 587d7b7e367417b2b2512b24
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title: 使用三元運算符
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challengeType: 1
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forumTopicId: 301181
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dashedName: use-the-conditional-ternary-operator
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---
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# --description--
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條件運算符( <dfn>conditional operator</dfn>,)(也稱爲三元運算符( <dfn>ternary operator</dfn>))的就像寫成一行的 if-else 表達式
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2021-06-30 20:47:19 +05:30
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語法是:`a ? b : c`, where `a` 是條件,當條件返回 `true` 的時候運行代碼 `b`,當條件返回 `false` 的時候運行代碼 `c`。
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2021-05-05 10:13:49 -07:00
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以下函數使用 `if/else` 語句來檢查條件:
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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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2021-08-07 00:02:45 +09:00
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return "b is greater or equal";
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2021-05-05 10:13:49 -07:00
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}
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}
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```
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這可以使用三元運算符重寫:
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```js
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function findGreater(a, b) {
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2021-08-07 00:02:45 +09:00
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return a > b ? "a is greater" : "b is greater or equal";
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2021-05-05 10:13:49 -07:00
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}
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```
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# --instructions--
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在 `checkEqual` 函數中使用三元運算符檢查兩個數字是否相等。 函數應該返回 `Equal` 或字符串 `Not Equal`。
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# --hints--
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`checkEqual` 應該使用條件運算符。
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```js
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assert(/.+?\s*?\?\s*?.+?\s*?:\s*?.+?/.test(code));
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```
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`checkEqual(1, 2)` 應該返回字符串 `Not Equal`
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```js
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assert(checkEqual(1, 2) === 'Not Equal');
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```
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`checkEqual(1, 1)` 應該返回字符串 `Equal`
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```js
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assert(checkEqual(1, 1) === 'Equal');
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```
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`checkEqual(1, -1)` 應該返回字符串 `Not Equal`
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```js
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assert(checkEqual(1, -1) === 'Not Equal');
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```
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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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# --solutions--
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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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