JSON数组

In the previous articles, we have talked about what JSON is, why it\’s prevalent today, how it has popularised itself over the last decade and defeated XML in comparison? We have also broken down JSON, compared it to a typical JavaScript object and defined the various types of values we can have in JSON.

在之前的文章中，我们讨论了什么是JSON，为什么它在今天如此流行，在过去十年中它如何流行并在比较中击败了XML？我们还细分了JSON，将其与典型JavaScript对象进行比较，并定义了JSON中可以具有的各种类型的值。

In this article, we\’ll have a look at JSON arrays.

在本文中，我们将介绍JSON数组 。

{\'Name\": \'Yoshi\", 	\'LastName\":\"Tatsu\",\'Age\": 24, 	\'Weapons\": [\"Sword\",\"Shield\",\"Ninja blade\"]}

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Remember this example from JSON Objects? Here we have a JSON array too with the key of weapons. We have a simple JSON array of strings inside.

还记得JSON Objects的这个例子吗？这里我们也有一个带武器钥匙的JSON数组。我们内部有一个简单的字符串JSON数组 。

We know that array is a primitive data structure in most languages as it is in JavaScript. Especially in JavaScript, an array is a data structure having several data values inside it, all of which are the same type. All these values have contiguous allocation of memory. In JSON, the value corresponding to a certain key can be an array of almost anything- array of strings, array of numbers or integers, array of boolean values, array of objects and array of arrays too!

我们知道，就像大多数JavaScript语言一样，数组是大多数语言中的原始数据结构。特别是在JavaScript中，数组是一种内部具有多个数据值的数据结构，所有这些数据值都是同一类型。所有这些值都具有连续的内存分配。在JSON中，对应于某个键的值几乎可以是任何数组-字符串数组，数字或整数数组，布尔值数组，对象数组以及数组数组！

简单JSON数组的示例 (Example of s simple JSON array)

{\"Names\": [\"Tim\", \"John\", \"Lee\", \"FuzzySid\"]}

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And a simple JavaScript array would look like,

一个简单JavaScript数组看起来像是

[\"Tim\", \"John\", \"Lee\", \"FuzzySid\"]

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The only difference between a normal JavaScript Array and a JSON Array is the type of values the array can possess. A JSON array can only have numbers, strings, objects or boolean values whereas a JavaScript array any valid JavaScript expression like a function, data some dates etc.

普通JavaScript数组和JSON数组之间的唯一区别是数组可以拥有的值的类型。 JSON数组只能包含数字，字符串，对象或布尔值，而JavaScript数组则可以是任何有效JavaScript表达式(例如函数)，某些日期的数据等。

We can access a JSON array either using the index associated with it.

我们可以使用与其关联的索引来访问JSON数组 。

var pokemon={\"name\":\"Squirtles\",\"type\":\"water\",\"HP\":100,\"isEvolved\":false}

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Recall that this is a simple JSON object. Let\’s add some JSON array inside it.

回想一下，这是一个简单的JSON对象。让我们在其中添加一些JSON数组。

var pokemon={\"name\":\"Squirtles\",\"type\":\"water\",\"HP\":100,\"isEvolved\":false,\"evos\":[\"Watertortle\",\"Blastoise\"],\"AttackTypes\":[\"super-attack\",\"defense\",\"special-defense\"],\"Weakness\":[\"electric\",\"grass\"],\"attacks\":[\"Water-Gun\",\"Rain-Splash\",\"Bubble\",\"Sleepy-Ball\"],\"DefensePower\":[33,47,88,49]}pokemon;

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Output

输出量

{name: \"Squirtles\", type: \"water\", HP: 100, isEvolved: false, evos: Array(2), …}AttackTypes: (3) [\"super-attack\", \"defense\", \"special-defense\"]DefensePower: (4) [33, 47, 88, 49]HP: 100Weakness: (2) [\"electric\", \"grass\"]attacks: (4) [\"Water-Gun\", \"Rain-Splash\", \"Bubble\", \"Sleepy-Ball\"]evos: (2) [\"Watertortle\", \"Blastoise\"]isEvolved: falsename: \"Squirtles\"type: \"water\"__proto__: Object

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Let\’s access the JSON arrays using the indices now.

现在，使用索引访问JSON数组 。

pokemon.AttackTypes[2]

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Output

输出量

\"special-defense\"

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pokemon.AttackTypes[0]

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Output

输出量

\"super-attack\"

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pokemon.Weakness[1];

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Output

输出量

\"grass\"

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pokemon.DefensePower[3];

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Output

输出量

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We can also loop through the array either using a simple loop or using the forEach loop.

我们也可以使用简单循环或使用forEach循环遍历数组。

pokemon.DefensePower.forEach(def=>{console.log(def);});

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Output

输出量

33478849

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Now if after some healthy snacks our squirtle can increase it\’s defense values by 25, we can see how they would look like.

现在，如果吃了一些健康的零食后，我们的蠕虫可以将其防御值提高25，我们可以看到它们的外观。

pokemon.DefensePower.forEach(def=>{console.log(def+25);});

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Output

输出量

587211374

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And say we give our squirtle this super delicious and super healthy snack. So now it\’s defense powers actually increase.

并说我们给我们的这只超级美味和超级健康的零食。因此，现在国防实力实际上得到了提高。

for(let i in pokemon.DefensePower){pokemon.DefensePower[i]+=25;}pokemon;

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Output

输出量

{name: \"Squirtles\", type: \"water\", HP: 100, isEvolved: false, evos: Array(2), …}AttackTypes: (3) [\"super-attack\", \"defense\", \"special-defense\"]DefensePower: Array(4)0: 581: 722: 1133: 74length: 4__proto__: Array(0)HP: 100Weakness: (2) [\"electric\", \"grass\"]attacks: (4) [\"Water-Gun\", \"Rain-Splash\", \"Bubble\", \"Sleepy-Ball\"]evos: (2) [\"Watertortle\", \"Blastoise\"]isEvolved: falsename: \"Squirtles\"type: \"water\"__proto__: Object

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Now you got too attached with the little squirtle and don\’t want it to grow just yet. Let\’s remove the evos array.

现在，您对小松鼠过于迷恋，不希望它现在还没有增长。让我们删除evos数组。

delete pokemon.evos;truepokemon;

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Output

输出量

{name: \"Squirtles\", type: \"water\", HP: 100, isEvolved: false, AttackTypes: Array(3), …}AttackTypes: (3) [\"super-attack\", \"defense\", \"special-defense\"]DefensePower: (4) [58, 72, 113, 74]HP: 100Weakness: (2) [\"electric\", \"grass\"]attacks: (4) [\"Water-Gun\", \"Rain-Splash\", \"Bubble\", \"Sleepy-Ball\"]isEvolved: falsename: \"Squirtles\"type: \"water\"__proto__: Object

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We have deleted the evos array inside our JSON.

我们已经删除了JSON中的evos数组。

Thus we can perform read, write, update and delete operations on a JSON array and also use some common array methods just like in a regular JavaScript Array.

因此，我们可以在JSON数组上执行读，写，更新和删除操作，还可以像在常规JavaScript数组中一样使用一些常见的数组方法。