An article introducing the conversion method between arrays and JSON in PHP

With the development of Internet technology, front-end development is becoming more and more important, and PHP, as a very popular back-end language, also plays an important role in the front-end and back-end separation development. In the development of PHP, arrays and JSON are two indispensable concepts. It is often necessary to convert arrays into JSON format, or convert JSON strings into PHP arrays for operation. Therefore, this article will introduce the conversion method of arrays and JSON in PHP and give some common application cases.

1. Arrays in PHP

Arrays are one of the most commonly used data structures in PHP and can store a set of related data values. In PHP, arrays can be divided into the following two types:

1. Indexed array

Indexed array is the most common array type, and its elements start from 0 arranged by index. In PHP, you can create an indexed array by:

// 创建一个索引数组
$arr = array('a', 'b', 'c');

In an indexed array, you can access the array elements by using:

// 访问数组元素
echo $arr[0]; // 输出结果为 'a'
echo $arr[1]; // 输出结果为 'b'
echo $arr[2]; // 输出结果为 'c'

2. Associative array

Associative array is an array type that accesses array elements based on string index, each element has a specified key. In PHP, you can create an associative array in the following way:

// 创建一个关联数组
$user = array('name' => '小明', 'age' => 18, 'gender' => '男');

In an associative array, you can access the array elements in the following way:

// 访问数组元素
echo $user['name']; // 输出结果为 '小明'
echo $user['age']; // 输出结果为 18
echo $user['gender']; // 输出结果为 '男'

2. JSON in PHP

JSON (JavaScript Object Notation) is a lightweight data exchange format that is easy to read and write, and easy to parse and generate. In PHP, you can convert an array into a JSON-formatted string through the json_encode() function, or you can convert a JSON-formatted string into a PHP array through the json_decode() function.

1. Convert an array to a JSON-formatted string

In PHP, you can use the json_encode() function to convert an array to a JSON-formatted string. The following is a sample code:

// 创建一个数组
$arr = array('name' => '小明', 'age' => 18, 'gender' => '男');

// 将数组转换为JSON格式的字符串
$json = json_encode($arr);

// 输出结果
echo $json; // 输出结果为 '{"name":"\u5c0f\u660e","age":18,"gender":"\u7537"}'

It should be noted that the json_encode() function converts Chinese to Unicode encoding. If you want to output Chinese, you need to use the unicode_decode() function to decode. For example:

// 创建一个数组
$arr = array('name' => '小明', 'age' => 18, 'gender' => '男');

// 将数组转换为JSON格式的字符串
$json = json_encode($arr);

// 解码中文字符
$json = unicode_decode($json);

// 输出结果
echo $json; // 输出结果为 '{"name":"小明","age":18,"gender":"男"}'

2. Convert JSON formatted string to PHP array

In PHP, you can use the json_decode() function to convert JSON formatted string to PHP array. The following is a sample code:

// 定义一个JSON格式的字符串
$json = '{"name":"小明","age":18,"gender":"男"}';

// 将JSON格式的字符串转换为PHP数组
$arr = json_decode($json, true);

// 输出结果
var_dump($arr); // 输出结果为 array(3) { ["name"]=> string(6) "小明" ["age"]=> int(18) ["gender"]=> string(3) "男" }

It should be noted that when the second parameter in the json_decode() function is true, an associative array will be returned; when it is false, an object will be returned.

3. Application cases of arrays and JSON in PHP

1. Storing PHP arrays into files

In PHP, you can use file_put_contents() Function stores an array into a file. The following is the sample code:

// 创建一个数组
$arr = array('name' => '小明', 'age' => 18, 'gender' => '男');

// 将数组转换为JSON格式的字符串
$json = json_encode($arr);

// 将JSON字符串存储到文件中
file_put_contents('user.json', $json);

2. Read a JSON string from a file and convert it into a PHP array

In PHP, you can use the file_get_contents() function Read a JSON-formatted string from a file and convert it into a PHP array using the json_decode() function. The following is a sample code:

// 从文件中读取JSON格式的字符串
$json = file_get_contents('user.json');

// 将JSON格式的字符串转换为PHP数组
$arr = json_decode($json, true);

// 输出结果
var_dump($arr); // 输出结果为 array(3) { ["name"]=> string(6) "小明" ["age"]=> int(18) ["gender"]=> string(3) "男" }

3. Read the JSON data returned by the API in PHP

When using the API interface, you often need to read the JSON format returned from the server data. In PHP, you can use the following code to read the JSON data returned by the API:

// API接口地址
$url = 'https://api.example.com/users';

// 读取API返回的JSON数据
$json = file_get_contents($url);

// 将JSON格式的字符串转换为PHP数组
$arr = json_decode($json, true);

// 输出结果
var_dump($arr);

In short, arrays and JSON in PHP are two indispensable concepts in web development. Those who are proficient in arrays and JSON Using methods can make our development work more efficient and accurate.

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