2018-10-10 22:03:03 +00:00
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---
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id: 56533eb9ac21ba0edf2244cb
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2021-03-15 03:20:39 +00:00
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title: 操作复杂对象
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2018-10-10 22:03:03 +00:00
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challengeType: 1
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2020-04-29 10:29:13 +00:00
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videoUrl: 'https://scrimba.com/c/c9yNMfR'
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forumTopicId: 18208
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2021-01-13 02:31:00 +00:00
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dashedName: manipulating-complex-objects
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2018-10-10 22:03:03 +00:00
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---
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2020-12-16 07:37:30 +00:00
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# --description--
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2021-03-15 03:20:39 +00:00
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有时你可能希望将数据存储在一个灵活的数据结构(<dfn>Data Structure</dfn>)中。 JavaScript 对象是一种灵活的数据结构。 它可以储存字符串(<dfn>strings</dfn>)、数字(<dfn>numbers</dfn>)、布尔值(<dfn>booleans</dfn>)、数组(<dfn>arrays</dfn>)、函数(<dfn>functions</dfn>)和对象(<dfn>objects</dfn>)以及这些值的任意组合。
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2020-12-16 07:37:30 +00:00
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2021-03-15 03:20:39 +00:00
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这是一个复杂数据结构的示例:
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2020-04-29 10:29:13 +00:00
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```js
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var ourMusic = [
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{
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"artist": "Daft Punk",
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"title": "Homework",
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"release_year": 1997,
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"formats": [
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"CD",
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"Cassette",
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"LP"
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],
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"gold": true
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}
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];
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```
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2021-03-15 03:20:39 +00:00
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这是一个包含一个对象的数组。 该对象有关于专辑的各种元数据(<dfn>metadata</dfn>)。 它也有一个嵌套的 `formats` 数组。 可以将专辑添加到顶级数组来增加更多的专辑记录。 对象将数据以一种键 - 值对的形式保存。 在上面的示例中,`"artist": "Daft Punk"` 有一个键位 `artist` 值为 `Daft Punk` 的属性。 [JavaScript Object Notation](http://www.json.org/) 简称 `JSON` 是可以用于存储数据的数据交换格式。
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2020-04-29 10:29:13 +00:00
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```json
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{
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"artist": "Daft Punk",
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"title": "Homework",
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"release_year": 1997,
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"formats": [
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"CD",
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"Cassette",
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"LP"
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],
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"gold": true
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}
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```
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2021-03-15 03:20:39 +00:00
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**提示:**数组中有多个 JSON 对象的时候,对象与对象之间要用逗号隔开。
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2020-12-16 07:37:30 +00:00
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# --instructions--
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2018-10-10 22:03:03 +00:00
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2021-03-15 03:20:39 +00:00
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添加一个新专辑到 `myMusic` 数组。 添加 `artist` 和 `title` 字符串,`release_year` 数字和 `formats` 字符串数组。
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2020-12-16 07:37:30 +00:00
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# --hints--
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2021-03-15 03:20:39 +00:00
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`myMusic` 应该是一个数组
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```js
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assert(Array.isArray(myMusic));
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2018-10-10 22:03:03 +00:00
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```
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2021-03-15 03:20:39 +00:00
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`myMusic` 应该至少包含两个元素
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2018-10-10 22:03:03 +00:00
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2020-12-16 07:37:30 +00:00
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```js
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assert(myMusic.length > 1);
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```
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2018-10-10 22:03:03 +00:00
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2021-03-15 03:20:39 +00:00
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`myMusic[1]` 应该是一个对象
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2018-10-10 22:03:03 +00:00
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```js
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assert(typeof myMusic[1] === 'object');
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```
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2021-03-15 03:20:39 +00:00
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`myMusic[1]` 至少要包含四个属性
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2018-10-10 22:03:03 +00:00
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```js
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assert(Object.keys(myMusic[1]).length > 3);
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2018-10-10 22:03:03 +00:00
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```
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2021-03-15 03:20:39 +00:00
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`myMusic[1]` 应该包含一个类型为字符串的 `artist` 的属性
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2018-10-10 22:03:03 +00:00
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2020-12-16 07:37:30 +00:00
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```js
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assert(
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myMusic[1].hasOwnProperty('artist') && typeof myMusic[1].artist === 'string'
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);
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```
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2018-10-10 22:03:03 +00:00
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`myMusic[1]` 应该包含一个类型为字符串的 `title` 属性
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2018-10-10 22:03:03 +00:00
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```js
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2020-12-16 07:37:30 +00:00
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assert(
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myMusic[1].hasOwnProperty('title') && typeof myMusic[1].title === 'string'
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);
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2018-10-10 22:03:03 +00:00
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```
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2021-03-15 03:20:39 +00:00
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`myMusic[1]` 应该包含一个类型为数字的 `release_year` 属性
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2018-10-10 22:03:03 +00:00
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2020-12-16 07:37:30 +00:00
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```js
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assert(
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myMusic[1].hasOwnProperty('release_year') &&
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typeof myMusic[1].release_year === 'number'
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);
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```
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2018-10-10 22:03:03 +00:00
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2021-03-15 03:20:39 +00:00
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`myMusic[1]` 应该包含一个类型为数组的 `formats` 属性
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2018-10-10 22:03:03 +00:00
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2020-12-16 07:37:30 +00:00
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```js
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assert(
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myMusic[1].hasOwnProperty('formats') && Array.isArray(myMusic[1].formats)
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);
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```
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2021-03-15 03:20:39 +00:00
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`formats`应该是一个至少包含两个字符串元素的数组
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2020-04-29 10:29:13 +00:00
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2018-10-10 22:03:03 +00:00
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```js
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2020-12-16 07:37:30 +00:00
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assert(
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myMusic[1].formats.every(function (item) {
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return typeof item === 'string';
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}) && myMusic[1].formats.length > 1
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);
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2018-10-10 22:03:03 +00:00
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```
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2020-04-29 10:29:13 +00:00
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2021-01-13 02:31:00 +00:00
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# --seed--
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## --after-user-code--
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```js
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(function(x){ if (Array.isArray(x)) { return JSON.stringify(x); } return "myMusic is not an array"})(myMusic);
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```
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## --seed-contents--
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```js
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var myMusic = [
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{
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"artist": "Billy Joel",
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"title": "Piano Man",
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"release_year": 1973,
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"formats": [
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"CD",
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"8T",
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"LP"
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],
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"gold": true
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}
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// Add a record here
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];
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```
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2020-12-16 07:37:30 +00:00
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# --solutions--
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2021-01-13 02:31:00 +00:00
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```js
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var myMusic = [
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{
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"artist": "Billy Joel",
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"title": "Piano Man",
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"release_year": 1973,
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"formats": [
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"CS",
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"8T",
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"LP" ],
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"gold": true
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},
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{
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"artist": "ABBA",
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"title": "Ring Ring",
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"release_year": 1973,
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"formats": [
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"CS",
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"8T",
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"LP",
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"CD",
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]
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}
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];
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```
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