How to convert array into json string in php

In recent years, JSON (JavaScript Object Notation), as a lightweight data exchange format, has become more and more popular among developers. In PHP, we can easily convert arrays into JSON strings. Let’s take a deeper look at this process.

1. What is JSON?

JSON is a lightweight data format that is formatted like a JavaScript object and can be used to simply store and transmit data. JSON consists of two structures: key/value pairs and arrays. JSON supports a variety of data types, including strings, numbers, Boolean values, arrays, objects, and more.

The following is a simple JSON example:

{
    "name": "Tom",
    "age": 20,
    "is_student": true,
    "hobbies": ["reading", "writing", "swimming"],
    "address": {
        "street": "123 Main St",
        "city": "New York",
        "state": "NY"
    }
}

2. Convert the array to a JSON string

In PHP, we can use json_encode() Function converts an array into a JSON string. This function accepts an array as a parameter and returns a string whose JSON string representation it is.

The following is a simple example of converting an array into a JSON string:

<?php // 定义一个数组
$data = array(
    "name" => "Tom",
    "age" => 20,
    "is_student" => true,
    "hobbies" => array("reading", "writing", "swimming"),
    "address" => array(
        "street" => "123 Main St",
        "city" => "New York",
        "state" => "NY"
    )
);

// 将数组转换为 JSON 字符串
$json = json_encode($data);

// 打印 JSON 字符串
echo $json;
?>

Executing the above code will output the following JSON string:

{"name":"Tom","age":20,"is_student":true,"hobbies":["reading","writing","swimming"],"address":{"street":"123 Main St","city":"New York","state":"NY"}}

We can see, json_encode() The function converts array format data into JSON format string.

3. Dealing with problems during the conversion process

Although the json_encode() function is very convenient, the following problems may occur when processing large and complex arrays:

1. Chinese garbled characters

When the array contains Chinese characters, the json_encode() function may convert them into Unicode codes, resulting in JSON characters Garbled characters appear in the string. To avoid this problem, we can convert it into Chinese characters by setting the JSON_UNESCAPED_UNICODE parameter.

For example:

<?php header(&#39;Content-type: application/json;charset=utf-8&#39;); // 设置字符集
$data = array(
    "name" => "张三",
    "age" => 23
);
echo json_encode($data, JSON_UNESCAPED_UNICODE);
?>

2. References appear inside the array

If there are references inside the array, that is, some values ​​of the array are the same as other values, then in An error occurs when converting to a JSON string. In order to solve this problem, we can use the json_last_error() function to judge before conversion. If there is a reference, we can pass the second parameter JSON_PARTIAL_OUTPUT_ON_ERROR# of json_encode() ## to exclude output and print an error message.

For example:

<?php $data = array(
    "name" => "张三",
    "gender" => "男",
    "scores" => array(90, 80, 70),
    "top" => &$data["scores"][0]
);

$json = json_encode($data, JSON_PARTIAL_OUTPUT_ON_ERROR);

if (json_last_error() !== JSON_ERROR_NONE) {
    echo json_last_error_msg(); // 输出错误信息
}
else {
    echo $json; // 输出 JSON 字符串
}
?>

By using the above method, we can convert the array into a JSON string more stably and safely, which can be applied to different scenarios such as web development and client development.

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