Files

122 lines
1.8 KiB
Markdown
Raw Permalink Normal View History

---
id: 56533eb9ac21ba0edf2244cd
title: 訪問嵌套數組
challengeType: 1
videoUrl: 'https://scrimba.com/c/cLeGDtZ'
forumTopicId: 16160
dashedName: accessing-nested-arrays
---
# --description--
在之前的挑戰中,我們學習了在對象中嵌套對象和數組。 與訪問嵌套對象類似,數組的方括號可以用來對嵌套數組進行鏈式訪問。
下面是訪問嵌套數組的例子:
```js
const ourPets = [
{
animalType: "cat",
names: [
"Meowzer",
"Fluffy",
"Kit-Cat"
]
},
{
animalType: "dog",
names: [
"Spot",
"Bowser",
"Frankie"
]
}
];
ourPets[0].names[1];
ourPets[1].names[0];
```
`ourPets[0].names[1]` 應該是字符串 `Fluffy` 並且 `ourPets[1].names[0]` 應該是字符串 `Spot`
# --instructions--
使用點和方括號,將變量 `secondTree` 的值設置爲 `myPlants` 對象中 `trees` 列表的第二個項目。
# --hints--
`secondTree` 應該等於字符串 `pine`
```js
assert(secondTree === 'pine');
```
你的代碼應該使用點號和方括號訪問 `myPlants`
```js
assert(/=\s*myPlants\[1\].list\[1\]/.test(code));
```
# --seed--
## --after-user-code--
```js
(function(x) {
if(typeof x != 'undefined') {
return "secondTree = " + x;
}
return "secondTree is undefined";
})(secondTree);
```
## --seed-contents--
```js
const myPlants = [
{
type: "flowers",
list: [
"rose",
"tulip",
"dandelion"
]
},
{
type: "trees",
list: [
"fir",
"pine",
"birch"
]
}
];
const secondTree = "";
```
# --solutions--
```js
const myPlants = [
{
type: "flowers",
list: [
"rose",
"tulip",
"dandelion"
]
},
{
type: "trees",
list: [
"fir",
"pine",
"birch"
]
}
];
const secondTree = myPlants[1].list[1];
```