How to convert array to JSON format using PHP

In web development, it is often necessary to convert PHP's associative array or numeric index array into JSON format in order to display it on the front-end page or make API calls. This requirement is very common in the development of modern web applications.

This article will tell you how to use PHP to convert an array into JSON format.

What is JSON?

JSON means "JavaScript Object Notation", which is a lightweight data exchange format that is highly readable, easy to write and parse. The JSON format is usually used to transmit data over the network and is used to represent simple data structures. For example, the string representation of JSON can contain arrays, associative arrays (that is, associative arrays in PHP), and even multi-layer nested data structures.

Convert PHP array to JSON

There is a built-in function named json_encode in PHP, which is used to convert PHP array into JSON format. The syntax of the json_encode function is as follows:

json_encode($value, $options = 0, $depth = 512);

• $value: required parameter, the PHP array to be converted.
• $options: Optional parameters, control the format of generated JSON. For details, please check the official PHP documentation.
• $depth: Optional parameter, set the maximum depth of nesting to avoid infinite recursion.

The following is a basic usage example:

<?php
// 创建一个PHP数组
$data = array(
  &#39;name&#39; => 'Tom',
  'age' => 26,
  'hobby' => array('coding', 'reading', 'swimming')
);

// 将PHP数组转化成JSON格式
$json = json_encode($data);

// 输出JSON格式的数据
echo $json;
?>

In the above code, we use the json_encode function to convert the PHP array into a JSON format character string and then output it to the browser. It is very convenient to use the echo function to output JSON data, but be careful to avoid including HTML tags or scripts in the JSON data, which may lead to XSS attacks. You can use the htmlentities function to convert the JSON data righteous.

Processing associative arrays

In PHP, associative arrays are a very common data type, which refer to arrays with string key names. When converting an associative array into JSON format, the key names become property names in the JSON object. The following is a simple example:

<?php
// 创建一个关联数组
$info = array(
  &#39;name&#39; => 'Tom',
  'email' => 'tom@example.com',
  'phone' => '13888888888'
);

// 转化成JSON格式
$json = json_encode($info);

// 输出JSON格式的数据
echo $json;
?>

The output of the above code is as follows:

{
  "name": "Tom",
  "email": "tom@example.com",
  "phone": "13888888888"
}

Processing numeric index arrays

Numeric index arrays are another common type in PHP Data type refers to an array with integer key names. When converting a numeric index array into JSON format, the values ​​in the array will become elements in the JSON array, and the numeric index will be automatically converted to a numeric type.

The following is a simple example:

<?php
// 创建一个数字索引数组
$numbers = array(10, 20, 30, 40);

// 转化成JSON格式
$json = json_encode($numbers);

// 输出JSON格式的数据
echo $json;
?>

The output of the above code is as follows:

[10,20,30,40]

Array nesting

In PHP, arrays can Nesting means that arrays can be used as elements or attribute values ​​of other arrays. When converting a nested array into JSON format, you can get the form of a nested JSON object or a JSON array, depending on the specific situation.

The following is an example:

<?php
// 创建一个嵌套数组
$data = array(
  &#39;name&#39; => 'Tom',
  'age' => 26,
  'languages' => array('PHP', 'JavaScript', 'Python'),
  'contact' => array(
    'email' => 'tom@example.com',
    'phone' => '13888888888'
  )
);

// 转化成JSON格式
$json = json_encode($data);

// 输出JSON格式的数据
echo $json;
?>

The output of the above code is as follows:

{
  "name": "Tom",
  "age": 26,
  "languages": [
    "PHP",
    "JavaScript",
    "Python"
  ],
  "contact": {
    "email": "tom@example.com",
    "phone": "13888888888"
  }
}

Summary

PHP provides a built-in function json_encode, you can quickly and easily convert PHP arrays into JSON format strings. By using the json_encode function, we can convert associative arrays and numeric index arrays in PHP into objects and arrays in JSON format, and can handle nested arrays. In short, use json_encodeThe function can easily generate standardized JSON format data.

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