87 lines
2.0 KiB
Markdown
87 lines
2.0 KiB
Markdown
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---
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id: 587d7b7c367417b2b2512b1b
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title: 使用 delete 關鍵字刪除對象屬性
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challengeType: 1
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forumTopicId: 301168
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dashedName: use-the-delete-keyword-to-remove-object-properties
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---
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# --description--
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現在我們已經學習了什麼是對象以及對象的基本特性和用途。 總之，對象是以鍵值對的形式，靈活、直觀地存儲結構化數據的一種方式，***而且***，通過對象的屬性查找屬性值是速度很快的操作。 在本章餘下的挑戰中，我們來了解一下對象的幾種常用操作，這樣你能更好地在代碼中使用這個十分有用的數據結構：對象。
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在之前的挑戰中，我們已經試過添加和修改對象中的鍵值對。 現在我們來看看如何從一個對象中*移除*一個鍵值對。
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我們再來回顧一下上一個挑戰中的 `foods` 對象。 如果我們想移除 `apples` 屬性，可以像這樣使用 `delete` 關鍵字：
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```js
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delete foods.apples;
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```
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# --instructions--
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請使用 delete 關鍵字來移除 `foods` 中的 `oranges`、`plums` 和 `strawberries` 屬性。
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# --hints--
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`foods` 對象應只包含 3 個屬性：`apples`、`grapes` 和 `bananas`。
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```js
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assert(
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!foods.hasOwnProperty('oranges') &&
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!foods.hasOwnProperty('plums') &&
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!foods.hasOwnProperty('strawberries') &&
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Object.keys(foods).length === 3
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);
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```
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應使用 `delete` 關鍵字來移除 `oranges`、`plums` 和 `strawberries` 屬性。
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```js
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assert(
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code.search(/oranges:/) !== -1 &&
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code.search(/plums:/) !== -1 &&
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code.search(/strawberries:/) !== -1
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);
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```
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# --seed--
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## --seed-contents--
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```js
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let foods = {
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apples: 25,
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oranges: 32,
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plums: 28,
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bananas: 13,
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grapes: 35,
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strawberries: 27
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};
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// Only change code below this line
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// Only change code above this line
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console.log(foods);
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```
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# --solutions--
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```js
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let foods = {
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apples: 25,
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oranges: 32,
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plums: 28,
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bananas: 13,
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grapes: 35,
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strawberries: 27
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};
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delete foods.oranges;
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delete foods.plums;
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delete foods.strawberries;
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console.log(foods);
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```
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