JSON Basic Tutorial

JSON Array

JSON arrays are similar to JavaScript arrays.

JSON arrays represent an ordered list of values. It can store strings, numbers, boolean values, or objects in a JSON array.

JSON object arrays

An array can be the value of an object property.

Example

var myJSON = {
　　"name":"Seagull",
　　"age":22,
　　"friends": ["Deadpool", "Hulk", "Thanos"]
}

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Accessing array values

You can access array values by using the index of each element in the array.

Example

var myJSON = {
　　"name":"Seagull",
　　"age":22,
　　"friends": ["Deadpool", "Hulk", "Thanos"]
}
myJSON.friends[2]　　//　returns "Thanos"

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Iterating over an array

Thefor-inLoops can be used to iterate over arrays.

Example

var myJSON = {
　　"name":"Seagull",
　　"age":22,
　　"friends": ["Deadpool", "Hulk", "Thanos"]
}
for (let x in myJSON.friends) {
document.getElementById("output").innerHTML　+= myJSON.friends[x];
}

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Nested Arrays in JSON Objects

In nested arrays, another array can also be a value of an array.

Example

var myJSON = {
　　"name":"Seagull",
　　"age":22,
　　"friends": [
　　{"heroName": "Deadpool", "skills": ["Martial artist", "Assassin"]},
　　{"heroName": "Hulk", "skills": ["Superhuman Speed", "Superhuman Strength"]},　
　　{"heroName": "Thanos", "skills": ["Telepathy", "Superhuman senses"]}
　　]　
}
myJSON.friends[2].heroName;　　//　returns "Thanos"

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nestedfor-inLoops can be used to access arrays within arrays.

Example

for(let i in myJSON.friends) {
　　　x　+= "<h3>"　+　myJSON.friends[i].heroName　+　"</h3>";
　　　for(let j in myJSON.friends[i].skills) {
　　　　　　x　+= myJSON.friends[i].skills[j]　+　"<br>";
　　　}
}
document.getElementById("output").innerHTML = x;

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Modify Array Values

Index numbers can be used to modify values.

Example

myJSON.friends[2] = "Ant-man";

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Delete Array Items

You can use the delete keyword to remove values from an array.

Example

2]

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JSON PHP JSON Object (Object)