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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2020-12-16 07:37:30 +00:00
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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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2021-05-09 19:42:02 +00:00
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`myMusic`应该有至少2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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2021-05-09 19:42:02 +00:00
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`myMusic`元素数组中应该是物体
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2018-10-10 22:03:03 +00:00
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```js
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myMusic.forEach(object => {assert.typeOf(object, 'object')})
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2020-12-16 07:37:30 +00:00
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```
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2021-05-09 19:42:02 +00:00
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`myMusic` 中的对象应该至少有 4 个属性。
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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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myMusic.forEach(object => {assert(Object.keys(object).length > 3); });
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2018-10-10 22:03:03 +00:00
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```
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2021-05-09 19:42:02 +00:00
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`myMusic` 中的对象应该包含一个类型为字符串的属性 `artist`。
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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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myMusic.forEach(object => {
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assert.containsAllKeys(object, ['artist']);
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assert.typeOf(object.artist, 'string')
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})
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2020-12-16 07:37:30 +00:00
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```
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2018-10-10 22:03:03 +00:00
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2021-05-09 19:42:02 +00:00
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`myMusic` 中的对象应该包含一个类型为字符串的属性 `title`。
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2018-10-10 22:03:03 +00:00
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```js
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2021-05-09 19:42:02 +00:00
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myMusic.forEach(object => {
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assert.containsAllKeys(object, ['title']);
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assert.typeOf(object.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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2021-05-09 19:42:02 +00:00
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`myMusic` 中的对象应该包含一个类型为数字的属性 `release_year`。
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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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2021-05-09 19:42:02 +00:00
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myMusic.forEach(object => {
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assert.containsAllKeys(object, ['release_year']);
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assert.typeOf(object.release_year, 'number')
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})
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2020-12-16 07:37:30 +00:00
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```
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2018-10-10 22:03:03 +00:00
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2021-05-09 19:42:02 +00:00
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`myMusic` 中的对象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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2021-05-09 19:42:02 +00:00
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myMusic.forEach(object => {
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assert.containsAllKeys(object, ['formats']);
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assert.typeOf(object.formats, 'array')
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})
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2020-12-16 07:37:30 +00:00
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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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2021-05-09 19:42:02 +00:00
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myMusic.forEach(object => {
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object.formats.forEach(format => {
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assert.typeOf(format, 'string')
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});
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assert.isAtLeast(object.formats.length, 2)
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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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];
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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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