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---
id: 56bbb991ad1ed5201cd392cd
title: 使用 shift() 操作數組
challengeType: 1
videoUrl: 'https://scrimba.com/c/cRbVETW'
forumTopicId: 18238
dashedName: manipulate-arrays-with-shift
---
# --description--
`pop()` 函數用來移出數組中最後一個元素。 如果想要移出第一個元素要怎麼辦呢?
這時候我們就需要 `.shift()` 了。 它的工作原理就像 `.pop()`,但它移除的是第一個元素,而不是最後一個。
示例:
```js
const ourArray = ["Stimpson", "J", ["cat"]];
const removedFromOurArray = ourArray.shift();
```
`removedFromOurArray` 值爲 `Stimpson``ourArray` 值爲 `["J", ["cat"]]`
# --instructions--
使用 `.shift()` 函數從 `myArray` 中刪除第一項,並將“移除的值”值分配給新變量 `removedFromMyArray`
# --hints--
`myArray` 應該只包含 `[["dog", 3]]`
```js
assert(
(function (d) {
if (d[0][0] == 'dog' && d[0][1] === 3 && d[1] == undefined) {
return true;
} else {
return false;
}
})(myArray)
);
```
`removedFromMyArray` 應該包含 `["John", 23]`
```js
assert(
(function (d) {
if (
d[0] == 'John' &&
d[1] === 23 &&
typeof removedFromMyArray === 'object'
) {
return true;
} else {
return false;
}
})(removedFromMyArray)
);
```
# --seed--
## --after-user-code--
```js
if (typeof removedFromMyArray !== 'undefined') (function(y, z){return 'myArray = ' + JSON.stringify(y) + ' & removedFromMyArray = ' + JSON.stringify(z);})(myArray, removedFromMyArray);
```
## --seed-contents--
```js
// Setup
const myArray = [["John", 23], ["dog", 3]];
// Only change code below this line
```
# --solutions--
```js
const myArray = [["John", 23], ["dog", 3]];
// Only change code below this line
const removedFromMyArray = myArray.shift();
```