101 lines
2.0 KiB
Markdown
101 lines
2.0 KiB
Markdown
---
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id: 56533eb9ac21ba0edf2244c7
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title: 通過點號表示法訪問對象屬性
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challengeType: 1
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videoUrl: 'https://scrimba.com/c/cGryJs8'
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forumTopicId: 16164
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dashedName: accessing-object-properties-with-dot-notation
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---
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# --description--
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和訪問數組類似,訪問對象屬性有兩種方式:點號表示法(`.`)和方括號表示法(`[]`)。
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如果我們已經提前知道要訪問的屬性名,使用點號表示法是最方便的。
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這裏是一個用點符號(`.`)讀取對象屬性的示例:
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```js
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const myObj = {
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prop1: "val1",
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prop2: "val2"
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};
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const prop1val = myObj.prop1;
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const prop2val = myObj.prop2;
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```
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`prop1val` 的值將爲字符串 `val1`,並且`prop2val` 的值將爲字符串 `val2`。
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# --instructions--
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使用點號讀取 `testObj` 的屬性值。 將變量 `hatValue` 的值設置爲該對象的 `hat` 屬性的值,並將變量 `shirtValue` 的值設置爲該對象的 `shirt` 屬性的值。
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# --hints--
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`hatValue` 應該是一個字符串
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```js
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assert(typeof hatValue === 'string');
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```
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`hatValue` 的值應該爲字符串 `ballcap`
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```js
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assert(hatValue === 'ballcap');
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```
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`shirtValue` 應該是一個字符串
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```js
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assert(typeof shirtValue === 'string');
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```
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`shirtValue` 的值應該爲字符串 `jersey`
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```js
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assert(shirtValue === 'jersey');
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```
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你應該使用兩個點號
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```js
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assert(code.match(/testObj\.\w+/g).length > 1);
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```
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# --seed--
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## --after-user-code--
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```js
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(function(a,b) { return "hatValue = '" + a + "', shirtValue = '" + b + "'"; })(hatValue,shirtValue);
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```
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## --seed-contents--
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```js
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// Setup
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const testObj = {
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"hat": "ballcap",
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"shirt": "jersey",
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"shoes": "cleats"
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};
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// Only change code below this line
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const hatValue = testObj; // Change this line
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const shirtValue = testObj; // Change this line
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```
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# --solutions--
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```js
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const testObj = {
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"hat": "ballcap",
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"shirt": "jersey",
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"shoes": "cleats"
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};
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const hatValue = testObj.hat;
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const shirtValue = testObj.shirt;
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```
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